diff --git a/Contentstack.Management.Core.Tests/Contentstack.cs b/Contentstack.Management.Core.Tests/Contentstack.cs
index e69153c..7ff2492 100644
--- a/Contentstack.Management.Core.Tests/Contentstack.cs
+++ b/Contentstack.Management.Core.Tests/Contentstack.cs
@@ -16,17 +16,6 @@ namespace Contentstack.Management.Core.Tests
 {
     public class Contentstack
     {
-        private static readonly Lazy<ContentstackClient>
-        client =
-        new Lazy<ContentstackClient>(() =>
-        {
-            ContentstackClientOptions options = Config.GetSection("Contentstack").Get<ContentstackClientOptions>();
-            var handler = new LoggingHttpHandler();
-            var httpClient = new HttpClient(handler);
-            return new ContentstackClient(httpClient, options);
-        });
-
-
         private static readonly Lazy<IConfigurationRoot>
         config =
         new Lazy<IConfigurationRoot>(() =>
@@ -46,13 +35,28 @@ private static readonly Lazy<IConfigurationRoot>
             return Config.GetSection("Contentstack:Organization").Get<OrganizationModel>();
         });
 
-        public static ContentstackClient Client { get { return client.Value; } }
         public static IConfigurationRoot Config{ get { return config.Value; } }
         public static NetworkCredential Credential { get { return credential.Value; } }
         public static OrganizationModel Organization { get { return organization.Value; } }
 
         public static StackModel Stack { get; set; }
 
+        /// <summary>
+        /// Creates a new ContentstackClient, logs in via the Login API (never from config),
+        /// and returns the authenticated client. Callers are responsible for calling Logout()
+        /// when done.
+        /// </summary>
+        public static ContentstackClient CreateAuthenticatedClient()
+        {
+            ContentstackClientOptions options = Config.GetSection("Contentstack").Get<ContentstackClientOptions>();
+            options.Authtoken = null;
+            var handler = new LoggingHttpHandler();
+            var httpClient = new HttpClient(handler);
+            var client = new ContentstackClient(httpClient, options);
+            client.Login(Credential);
+            return client;
+        }
+
         public static T serialize<T>(JsonSerializer serializer, string filePath)
         {
             string response = GetResourceText(filePath);
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack001_LoginTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack001_LoginTest.cs
index eef6538..766dd7b 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack001_LoginTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack001_LoginTest.cs
@@ -5,9 +5,6 @@
 using Contentstack.Management.Core.Models;
 using Contentstack.Management.Core.Tests.Helpers;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
-using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.Options;
-using System.Threading;
 using Contentstack.Management.Core.Queryable;
 using Newtonsoft.Json.Linq;
 
@@ -16,7 +13,6 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack001_LoginTest
     {
-        private readonly IConfigurationRoot _configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();
 
         private static ContentstackClient CreateClientWithLogging()
         {
@@ -48,25 +44,24 @@ public void Test001_Should_Return_Failuer_On_Wrong_Login_Credentials()
 
         [TestMethod]
         [DoNotParallelize]
-        public void Test002_Should_Return_Failuer_On_Wrong_Async_Login_Credentials()
+        public async System.Threading.Tasks.Task Test002_Should_Return_Failuer_On_Wrong_Async_Login_Credentials()
         {
             TestOutputLogger.LogContext("TestScenario", "WrongCredentialsAsync");
             ContentstackClient client = CreateClientWithLogging();
             NetworkCredential credentials = new NetworkCredential("mock_user", "mock_pasword");
-            var response = client.LoginAsync(credentials);
-
-            response.ContinueWith((t) =>
-            {
-                if (t.IsCompleted && t.Status == System.Threading.Tasks.TaskStatus.Faulted)
-                {
-                    ContentstackErrorException errorException = t.Exception.InnerException as ContentstackErrorException;
-                    AssertLogger.AreEqual(HttpStatusCode.UnprocessableEntity, errorException.StatusCode, "StatusCode");
-                    AssertLogger.AreEqual("Looks like your email or password is invalid. Please try again or reset your password.", errorException.Message, "Message");
-                    AssertLogger.AreEqual("Looks like your email or password is invalid. Please try again or reset your password.", errorException.ErrorMessage, "ErrorMessage");
-                    AssertLogger.AreEqual(104, errorException.ErrorCode, "ErrorCode");
-                }
-            });
-            Thread.Sleep(3000);
+
+            try
+            {
+                await client.LoginAsync(credentials);
+                AssertLogger.Fail("Expected exception for wrong credentials");
+            }
+            catch (ContentstackErrorException errorException)
+            {
+                AssertLogger.AreEqual(HttpStatusCode.UnprocessableEntity, errorException.StatusCode, "StatusCode");
+                AssertLogger.AreEqual("Looks like your email or password is invalid. Please try again or reset your password.", errorException.Message, "Message");
+                AssertLogger.AreEqual("Looks like your email or password is invalid. Please try again or reset your password.", errorException.ErrorMessage, "ErrorMessage");
+                AssertLogger.AreEqual(104, errorException.ErrorCode, "ErrorCode");
+            }
         }
 
         [TestMethod]
@@ -304,5 +299,198 @@ public void Test011_Should_Prefer_Explicit_Token_Over_MfaSecret()
                 AssertLogger.Fail($"Unexpected exception type: {e.GetType().Name} - {e.Message}");
             }
         }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public void Test012_Should_Throw_InvalidOperation_When_Already_LoggedIn_Sync()
+        {
+            TestOutputLogger.LogContext("TestScenario", "AlreadyLoggedInSync");
+            ContentstackClient client = CreateClientWithLogging();
+
+            try
+            {
+                client.Login(Contentstack.Credential);
+                AssertLogger.IsNotNull(client.contentstackOptions.Authtoken, "Authtoken");
+
+                AssertLogger.ThrowsException<InvalidOperationException>(() =>
+                    client.Login(Contentstack.Credential), "AlreadyLoggedIn");
+
+                client.Logout();
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail($"Unexpected exception: {e.GetType().Name} - {e.Message}");
+            }
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public async System.Threading.Tasks.Task Test013_Should_Throw_InvalidOperation_When_Already_LoggedIn_Async()
+        {
+            TestOutputLogger.LogContext("TestScenario", "AlreadyLoggedInAsync");
+            ContentstackClient client = CreateClientWithLogging();
+
+            try
+            {
+                await client.LoginAsync(Contentstack.Credential);
+                AssertLogger.IsNotNull(client.contentstackOptions.Authtoken, "Authtoken");
+
+                await System.Threading.Tasks.Task.Run(() =>
+                    AssertLogger.ThrowsException<InvalidOperationException>(() =>
+                        client.LoginAsync(Contentstack.Credential).GetAwaiter().GetResult(), "AlreadyLoggedInAsync"));
+
+                await client.LogoutAsync();
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail($"Unexpected exception: {e.GetType().Name} - {e.Message}");
+            }
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public void Test014_Should_Throw_ArgumentNullException_For_Null_Credentials_Sync()
+        {
+            TestOutputLogger.LogContext("TestScenario", "NullCredentialsSync");
+            ContentstackClient client = CreateClientWithLogging();
+
+            AssertLogger.ThrowsException<ArgumentNullException>(() =>
+                client.Login(null), "NullCredentials");
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public void Test015_Should_Throw_ArgumentNullException_For_Null_Credentials_Async()
+        {
+            TestOutputLogger.LogContext("TestScenario", "NullCredentialsAsync");
+            ContentstackClient client = CreateClientWithLogging();
+
+            AssertLogger.ThrowsException<ArgumentNullException>(() =>
+                client.LoginAsync(null).GetAwaiter().GetResult(), "NullCredentialsAsync");
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public async System.Threading.Tasks.Task Test016_Should_Throw_ArgumentException_For_Invalid_MfaSecret_Async()
+        {
+            TestOutputLogger.LogContext("TestScenario", "InvalidMfaSecretAsync");
+            ContentstackClient client = CreateClientWithLogging();
+            NetworkCredential credentials = new NetworkCredential("test_user", "test_password");
+            string invalidMfaSecret = "INVALID_BASE32_SECRET!@#";
+
+            try
+            {
+                await client.LoginAsync(credentials, null, invalidMfaSecret);
+                AssertLogger.Fail("Expected ArgumentException for invalid MFA secret");
+            }
+            catch (ArgumentException)
+            {
+                AssertLogger.IsTrue(true, "ArgumentException thrown as expected for async");
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail($"Unexpected exception type: {e.GetType().Name} - {e.Message}");
+            }
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public void Test017_Should_Handle_Valid_Credentials_With_TfaToken_Sync()
+        {
+            TestOutputLogger.LogContext("TestScenario", "WrongTfaTokenSync");
+            ContentstackClient client = CreateClientWithLogging();
+
+            try
+            {
+                client.Login(Contentstack.Credential, "000000");
+                // Account does not have 2FA enabled — tfa_token is ignored by the API and login succeeds.
+                // This is a valid outcome; assert token is set and clean up.
+                AssertLogger.IsNotNull(client.contentstackOptions.Authtoken, "Authtoken");
+                client.Logout();
+            }
+            catch (ContentstackErrorException errorException)
+            {
+                // Account has 2FA enabled — wrong token is correctly rejected with 422.
+                AssertLogger.AreEqual(HttpStatusCode.UnprocessableEntity, errorException.StatusCode, "StatusCode");
+                AssertLogger.IsTrue(errorException.ErrorCode > 0, "TfaErrorCode");
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail($"Unexpected exception type: {e.GetType().Name} - {e.Message}");
+            }
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public async System.Threading.Tasks.Task Test018_Should_Handle_Valid_Credentials_With_TfaToken_Async()
+        {
+            TestOutputLogger.LogContext("TestScenario", "WrongTfaTokenAsync");
+            ContentstackClient client = CreateClientWithLogging();
+
+            try
+            {
+                await client.LoginAsync(Contentstack.Credential, "000000");
+                // Account does not have 2FA enabled — tfa_token is ignored by the API and login succeeds.
+                // This is a valid outcome; assert token is set and clean up.
+                AssertLogger.IsNotNull(client.contentstackOptions.Authtoken, "Authtoken");
+                await client.LogoutAsync();
+            }
+            catch (ContentstackErrorException errorException)
+            {
+                // Account has 2FA enabled — wrong token is correctly rejected with 422.
+                AssertLogger.AreEqual(HttpStatusCode.UnprocessableEntity, errorException.StatusCode, "StatusCode");
+                AssertLogger.IsTrue(errorException.ErrorCode > 0, "TfaErrorCodeAsync");
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail($"Unexpected exception type: {e.GetType().Name} - {e.Message}");
+            }
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public void Test019_Should_Not_Include_TfaToken_When_MfaSecret_Is_Empty_Sync()
+        {
+            TestOutputLogger.LogContext("TestScenario", "EmptyMfaSecretSync");
+            ContentstackClient client = CreateClientWithLogging();
+            NetworkCredential credentials = new NetworkCredential("mock_user", "mock_password");
+
+            try
+            {
+                client.Login(credentials, null, "");
+            }
+            catch (ContentstackErrorException errorException)
+            {
+                AssertLogger.AreEqual(HttpStatusCode.UnprocessableEntity, errorException.StatusCode, "StatusCode");
+                AssertLogger.AreEqual(104, errorException.ErrorCode, "ErrorCode");
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail($"Unexpected exception type: {e.GetType().Name} - {e.Message}");
+            }
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public async System.Threading.Tasks.Task Test020_Should_Not_Include_TfaToken_When_MfaSecret_Is_Null_Async()
+        {
+            TestOutputLogger.LogContext("TestScenario", "NullMfaSecretAsync");
+            ContentstackClient client = CreateClientWithLogging();
+            NetworkCredential credentials = new NetworkCredential("mock_user", "mock_password");
+
+            try
+            {
+                await client.LoginAsync(credentials, null, null);
+            }
+            catch (ContentstackErrorException errorException)
+            {
+                AssertLogger.AreEqual(HttpStatusCode.UnprocessableEntity, errorException.StatusCode, "StatusCode");
+                AssertLogger.AreEqual(104, errorException.ErrorCode, "ErrorCode");
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail($"Unexpected exception type: {e.GetType().Name} - {e.Message}");
+            }
+        }
     }
 }
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack002_OrganisationTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack002_OrganisationTest.cs
index 3d0d1d1..354278a 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack002_OrganisationTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack002_OrganisationTest.cs
@@ -13,6 +13,7 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack002_OrganisationTest
     {
+        private static ContentstackClient _client;
         private double _count;
         static string RoleUID = "";
         static string EmailSync = "testcs@contentstack.com";
@@ -21,6 +22,19 @@ public class Contentstack002_OrganisationTest
         static string InviteIDAsync = "";
         private readonly IFixture _fixture = new Fixture();
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestMethod]
         [DoNotParallelize]
         public void Test001_Should_Return_All_Organizations()
@@ -28,7 +42,7 @@ public void Test001_Should_Return_All_Organizations()
             TestOutputLogger.LogContext("TestScenario", "GetAllOrganizations");
             try
             {
-                Organization organization = Contentstack.Client.Organization();
+                Organization organization = _client.Organization();
 
                 ContentstackResponse contentstackResponse = organization.GetOrganizations();
 
@@ -50,7 +64,7 @@ public async System.Threading.Tasks.Task Test002_Should_Return_All_Organizations
             TestOutputLogger.LogContext("TestScenario", "GetAllOrganizationsAsync");
             try
             {
-                Organization organization = Contentstack.Client.Organization();
+                Organization organization = _client.Organization();
 
                 ContentstackResponse contentstackResponse = await organization.GetOrganizationsAsync();
 
@@ -73,7 +87,7 @@ public void Test003_Should_Return_With_Skipping_Organizations()
             TestOutputLogger.LogContext("TestScenario", "SkipOrganizations");
             try
             {
-                Organization organization = Contentstack.Client.Organization();
+                Organization organization = _client.Organization();
                 ParameterCollection collection = new ParameterCollection();
                 collection.Add("skip", 4);
                 ContentstackResponse contentstackResponse = organization.GetOrganizations(collection);
@@ -98,7 +112,7 @@ public void Test004_Should_Return_Organization_With_UID()
             {
                 var org = Contentstack.Organization;
                 TestOutputLogger.LogContext("OrganizationUid", org.Uid);
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
 
                 ContentstackResponse contentstackResponse = organization.GetOrganizations();
 
@@ -124,7 +138,7 @@ public void Test005_Should_Return_Organization_With_UID_Include_Plan()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
                 ParameterCollection collection = new ParameterCollection();
                 collection.Add("include_plan", true);
 
@@ -150,7 +164,7 @@ public void Test006_Should_Return_Organization_Roles()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
 
                 ContentstackResponse contentstackResponse = organization.Roles();
 
@@ -175,7 +189,7 @@ public async System.Threading.Tasks.Task Test007_Should_Return_Organization_Role
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
 
                 ContentstackResponse contentstackResponse = await organization.RolesAsync();
 
@@ -198,7 +212,7 @@ public void Test008_Should_Add_User_To_Organization()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
                 UserInvitation invitation = new UserInvitation()
                 {
                     Email = EmailSync,
@@ -230,7 +244,7 @@ public async System.Threading.Tasks.Task Test009_Should_Add_User_To_Organization
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
                 UserInvitation invitation = new UserInvitation()
                 {
                     Email = EmailAsync,
@@ -261,7 +275,7 @@ public void Test010_Should_Resend_Invite()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
 
                 ContentstackResponse contentstackResponse = organization.ResendInvitation(InviteID);
 
@@ -284,7 +298,7 @@ public async System.Threading.Tasks.Task Test011_Should_Resend_Invite()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
                 ContentstackResponse contentstackResponse = await organization.ResendInvitationAsync(InviteIDAsync);
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -306,7 +320,7 @@ public void Test012_Should_Remove_User_From_Organization()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
 
                 ContentstackResponse contentstackResponse = organization.RemoveUser(new System.Collections.Generic.List<string>() { EmailSync } );
 
@@ -329,7 +343,7 @@ public async System.Threading.Tasks.Task Test013_Should_Remove_User_From_Organiz
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
                 ContentstackResponse contentstackResponse = await organization.RemoveUserAsync(new System.Collections.Generic.List<string>() { EmailAsync });
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -351,7 +365,7 @@ public void Test014_Should_Get_All_Invites()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
 
                 ContentstackResponse contentstackResponse = organization.GetInvitations();
 
@@ -376,7 +390,7 @@ public async System.Threading.Tasks.Task Test015_Should_Get_All_Invites_Async()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
                 ContentstackResponse contentstackResponse = await organization.GetInvitationsAsync();
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -399,7 +413,7 @@ public void Test016_Should_Get_All_Stacks()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
 
                 ContentstackResponse contentstackResponse = organization.GetStacks();
 
@@ -424,7 +438,7 @@ public async System.Threading.Tasks.Task Test017_Should_Get_All_Stacks_Async()
             try
             {
                 var org = Contentstack.Organization;
-                Organization organization = Contentstack.Client.Organization(org.Uid);
+                Organization organization = _client.Organization(org.Uid);
                 ContentstackResponse contentstackResponse = await organization.GetStacksAsync();
 
                 var response = contentstackResponse.OpenJObjectResponse();
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack003_StackTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack003_StackTest.cs
index bcfe77b..eb4ba94 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack003_StackTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack003_StackTest.cs
@@ -11,6 +11,7 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack003_StackTest
     {
+        private static ContentstackClient _client;
         private readonly string _locale = "en-us";
         private string _stackName = "DotNet Management Stack";
         private string _updatestackName = "DotNet Management SDK Stack";
@@ -18,6 +19,19 @@ public class Contentstack003_StackTest
         
         private OrganizationModel _org = Contentstack.Organization;
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestMethod]
         [DoNotParallelize]
         public void Test001_Should_Return_All_Stacks()
@@ -25,7 +39,7 @@ public void Test001_Should_Return_All_Stacks()
             TestOutputLogger.LogContext("TestScenario", "ReturnAllStacks");
             try
             {
-                Stack stack = Contentstack.Client.Stack();
+                Stack stack = _client.Stack();
 
                 ContentstackResponse contentstackResponse = stack.GetAll();
 
@@ -45,7 +59,7 @@ public async System.Threading.Tasks.Task Test002_Should_Return_All_StacksAsync()
             TestOutputLogger.LogContext("TestScenario", "ReturnAllStacksAsync");
             try
             {
-                Stack stack = Contentstack.Client.Stack();
+                Stack stack = _client.Stack();
 
                 ContentstackResponse contentstackResponse = await stack.GetAllAsync();
 
@@ -66,7 +80,7 @@ public void Test003_Should_Create_Stack()
             TestOutputLogger.LogContext("TestScenario", "CreateStack");
             try
             {
-                Stack stack = Contentstack.Client.Stack();
+                Stack stack = _client.Stack();
                 ContentstackResponse contentstackResponse = stack.Create(_stackName, _locale, _org.Uid);
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -94,7 +108,7 @@ public void Test004_Should_Update_Stack()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
                 ContentstackResponse contentstackResponse = stack.Update(_updatestackName);
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -124,7 +138,7 @@ public async System.Threading.Tasks.Task Test005_Should_Update_Stack_Async()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
                 ContentstackResponse contentstackResponse = await stack.UpdateAsync(_updatestackName, _description);
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -152,7 +166,7 @@ public void Test006_Should_Fetch_Stack()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
                 ContentstackResponse contentstackResponse = stack.Fetch();
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -179,7 +193,7 @@ public async System.Threading.Tasks.Task Test007_Should_Fetch_StackAsync()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
                 ContentstackResponse contentstackResponse = await stack.FetchAsync();
 
                 var response = contentstackResponse.OpenJObjectResponse();
@@ -206,7 +220,7 @@ public void Test008_Add_Stack_Settings()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
                 StackSettings settings = new StackSettings()
                 {
                     StackVariables = new Dictionary<string, object>()
@@ -240,7 +254,7 @@ public void Test009_Stack_Settings()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
 
                 ContentstackResponse contentstackResponse = stack.Settings();
 
@@ -266,7 +280,7 @@ public void Test010_Reset_Stack_Settings()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
 
                 ContentstackResponse contentstackResponse = stack.ResetSettings();
 
@@ -292,7 +306,7 @@ public async System.Threading.Tasks.Task Test011_Add_Stack_Settings_Async()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
                 StackSettings settings = new StackSettings()
                 {
                     Rte = new Dictionary<string, object>()
@@ -324,7 +338,7 @@ public async System.Threading.Tasks.Task Test012_Reset_Stack_Settings_Async()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
 
                 ContentstackResponse contentstackResponse = await stack.ResetSettingsAsync();
 
@@ -350,7 +364,7 @@ public async System.Threading.Tasks.Task Test013_Stack_Settings_Async()
             TestOutputLogger.LogContext("StackApiKey", Contentstack.Stack.APIKey);
             try
             {
-                Stack stack = Contentstack.Client.Stack(Contentstack.Stack.APIKey);
+                Stack stack = _client.Stack(Contentstack.Stack.APIKey);
 
                 ContentstackResponse contentstackResponse = await stack.SettingsAsync();
 
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack004_ReleaseTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack004_ReleaseTest.cs
index 66f9014..cf5cb53 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack004_ReleaseTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack004_ReleaseTest.cs
@@ -14,15 +14,29 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack004_ReleaseTest
     {
+        private static ContentstackClient _client;
         private Stack _stack;
         private string _testReleaseName = "DotNet SDK Integration Test Release";
         private string _testReleaseDescription = "Release created for .NET SDK integration testing";
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestInitialize]
         public async Task Initialize()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
         }
 
 
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack011_GlobalFieldTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack011_GlobalFieldTest.cs
index 08f050b..d2d9f84 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack011_GlobalFieldTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack011_GlobalFieldTest.cs
@@ -12,14 +12,29 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack004_GlobalFieldTest
     {
+        private static ContentstackClient _client;
         private Stack _stack;
         private ContentModelling _modelling;
+
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestInitialize]
         public void Initialize ()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
-            _modelling = Contentstack.serialize<ContentModelling>(Contentstack.Client.serializer, "globalfield.json");
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
+            _modelling = Contentstack.serialize<ContentModelling>(_client.serializer, "globalfield.json");
         }
 
         [TestMethod]
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_ContentTypeTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_ContentTypeTest.cs
index a23d15c..f244d6a 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_ContentTypeTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_ContentTypeTest.cs
@@ -10,17 +10,31 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack005_ContentTypeTest
     {
+        private static ContentstackClient _client;
         private Stack _stack;
         private ContentModelling _singlePage;
         private ContentModelling _multiPage;
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestInitialize]
         public void Initialize ()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
-            _singlePage = Contentstack.serialize<ContentModelling>(Contentstack.Client.serializer, "singlepageCT.json");
-            _multiPage = Contentstack.serialize<ContentModelling>(Contentstack.Client.serializer, "multiPageCT.json");
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
+            _singlePage = Contentstack.serialize<ContentModelling>(_client.serializer, "singlepageCT.json");
+            _multiPage = Contentstack.serialize<ContentModelling>(_client.serializer, "multiPageCT.json");
         }
 
         [TestMethod]
@@ -93,7 +107,7 @@ public void Test005_Should_Update_Content_Type()
         {
             TestOutputLogger.LogContext("TestScenario", "UpdateContentType");
             TestOutputLogger.LogContext("ContentType", _multiPage.Uid);
-            _multiPage.Schema = Contentstack.serializeArray<List<Models.Fields.Field>>(Contentstack.Client.serializer, "contentTypeSchema.json"); ;
+            _multiPage.Schema = Contentstack.serializeArray<List<Models.Fields.Field>>(_client.serializer, "contentTypeSchema.json"); ;
             ContentstackResponse response = _stack.ContentType(_multiPage.Uid).Update(_multiPage);
             ContentTypeModel ContentType = response.OpenTResponse<ContentTypeModel>();
             AssertLogger.IsNotNull(response, "response");
@@ -113,7 +127,7 @@ public async System.Threading.Tasks.Task Test006_Should_Update_Async_Content_Typ
             try
             {
                 // Load the existing schema
-                _multiPage.Schema = Contentstack.serializeArray<List<Models.Fields.Field>>(Contentstack.Client.serializer, "contentTypeSchema.json");
+                _multiPage.Schema = Contentstack.serializeArray<List<Models.Fields.Field>>(_client.serializer, "contentTypeSchema.json");
                 
                 // Add a new text field to the schema
                 var newTextField = new Models.Fields.TextboxField
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_NestedGlobalFieldTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_NestedGlobalFieldTest.cs
index 545789a..c0e8f1d 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_NestedGlobalFieldTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack012_NestedGlobalFieldTest.cs
@@ -15,13 +15,27 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack008_NestedGlobalFieldTest
     {
+        private static ContentstackClient _client;
         private Stack _stack;
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestInitialize]
         public void Initialize()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
         }
 
         private ContentModelling CreateReferencedGlobalFieldModel()
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack013_AssetTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack013_AssetTest.cs
index 9d21420..2028a7f 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack013_AssetTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack013_AssetTest.cs
@@ -18,13 +18,27 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack006_AssetTest
     {
+        private static ContentstackClient _client;
         private Stack _stack;
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestInitialize]
         public void Initialize()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
         }
 
         [TestMethod]
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack014_EntryTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack014_EntryTest.cs
index 552ba07..93e6b5c 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack014_EntryTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack014_EntryTest.cs
@@ -14,13 +14,27 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack007_EntryTest
     {
+        private static ContentstackClient _client;
         private Stack _stack;
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestInitialize]
         public void Initialize()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
         }
 
         [TestMethod]
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack015_BulkOperationTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack015_BulkOperationTest.cs
index 6d9e573..9c61f86 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack015_BulkOperationTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack015_BulkOperationTest.cs
@@ -60,18 +60,21 @@ private static void AssertWorkflowCreated()
             AssertLogger.IsFalse(string.IsNullOrEmpty(_bulkTestWorkflowStage2Uid), "Workflow Stage 2 (New stage 2) was not set. " + reason, "WorkflowStage2Uid");
         }
 
+        private static ContentstackClient _client;
+
         /// <summary>
         /// Returns a Stack instance for the test run (used by ClassInitialize/ClassCleanup).
         /// </summary>
         private static Stack GetStack()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            return Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            return _client.Stack(response.Stack.APIKey);
         }
 
         [ClassInitialize]
         public static void ClassInitialize(TestContext context)
         {
+            _client = Contentstack.CreateAuthenticatedClient();
             try
             {
                 Stack stack = GetStack();
@@ -87,13 +90,15 @@ public static void ClassInitialize(TestContext context)
         public static void ClassCleanup()
         {
             // Intentionally no cleanup: workflow, publish rules, and entries are left so you can verify them in the UI.
+            try { _client?.Logout(); } catch { }
+            _client = null;
         }
 
         [TestInitialize]
         public async Task Initialize()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
 
             // Create test environment and release for bulk operations (for new stack)
             try
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack016_DeliveryTokenTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack016_DeliveryTokenTest.cs
index 9af15ba..fc30861 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack016_DeliveryTokenTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack016_DeliveryTokenTest.cs
@@ -15,40 +15,32 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack016_DeliveryTokenTest
     {
+        private static ContentstackClient _client;
         private Stack _stack;
         private string _deliveryTokenUid;
         private string _testEnvironmentUid = "test_delivery_environment";
         private DeliveryTokenModel _testTokenModel;
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
+        [ClassCleanup]
+        public static void ClassCleanup()
+        {
+            try { _client?.Logout(); } catch { }
+            _client = null;
+        }
+
         [TestInitialize]
         public async Task Initialize()
         {
             try
             {
-                // First, ensure the client is logged in
-                try
-                {
-                    ContentstackResponse loginResponse = Contentstack.Client.Login(Contentstack.Credential);
-                    if (!loginResponse.IsSuccessStatusCode)
-                    {
-                        AssertLogger.Fail($"Login failed: {loginResponse.OpenResponse()}");
-                    }
-                }
-                catch (Exception loginEx)
-                {
-                    // If already logged in, that's fine - continue with the test
-                    if (loginEx.Message.Contains("already logged in"))
-                    {
-                        Console.WriteLine("Client already logged in, continuing with test");
-                    }
-                    else
-                    {
-                        throw; // Re-throw if it's a different error
-                    }
-                }
-
-                StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-                _stack = Contentstack.Client.Stack(response.Stack.APIKey);
+                StackResponse response = StackResponse.getStack(_client.serializer);
+                _stack = _client.Stack(response.Stack.APIKey);
 
                 await CreateTestEnvironment();
 
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack017_TaxonomyTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack017_TaxonomyTest.cs
index ba8cf83..ba34b4c 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack017_TaxonomyTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack017_TaxonomyTest.cs
@@ -17,6 +17,7 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack017_TaxonomyTest
     {
+        private static ContentstackClient _client;
         private static string _taxonomyUid;
         private static string _asyncCreatedTaxonomyUid;
         private static string _importedTaxonomyUid;
@@ -30,11 +31,17 @@ public class Contentstack017_TaxonomyTest
         private Stack _stack;
         private TaxonomyModel _createModel;
 
+        [ClassInitialize]
+        public static void ClassInitialize(TestContext context)
+        {
+            _client = Contentstack.CreateAuthenticatedClient();
+        }
+
         [TestInitialize]
         public void Initialize()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            _stack = Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            _stack = _client.Stack(response.Stack.APIKey);
             if (_taxonomyUid == null)
                 _taxonomyUid = "taxonomy_integration_test_" + Guid.NewGuid().ToString("N").Substring(0, 8);
             _createdTermUids = _createdTermUids ?? new List<string>();
@@ -796,8 +803,8 @@ public void Test042_Should_Throw_When_Delete_NonExistent_Term()
 
         private static Stack GetStack()
         {
-            StackResponse response = StackResponse.getStack(Contentstack.Client.serializer);
-            return Contentstack.Client.Stack(response.Stack.APIKey);
+            StackResponse response = StackResponse.getStack(_client.serializer);
+            return _client.Stack(response.Stack.APIKey);
         }
 
         [ClassCleanup]
@@ -900,6 +907,9 @@ public static void Cleanup()
             {
                 Console.WriteLine($"[Cleanup] Cleanup failed: {ex.Message}");
             }
+
+            try { _client?.Logout(); } catch { }
+            _client = null;
         }
     }
 }
diff --git a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack999_LogoutTest.cs b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack999_LogoutTest.cs
index cf8a4ca..538387b 100644
--- a/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack999_LogoutTest.cs
+++ b/Contentstack.Management.Core.Tests/IntegrationTest/Contentstack999_LogoutTest.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Net.Http;
 using Contentstack.Management.Core.Tests.Helpers;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
@@ -7,24 +8,76 @@ namespace Contentstack.Management.Core.Tests.IntegrationTest
     [TestClass]
     public class Contentstack999_LogoutTest
     {
+        private static ContentstackClient CreateClientWithLogging()
+        {
+            var handler = new LoggingHttpHandler();
+            var httpClient = new HttpClient(handler);
+            return new ContentstackClient(httpClient, new ContentstackClientOptions());
+        }
+
         [TestMethod]
         [DoNotParallelize]
-        public void Test001_Should_Return_Success_On_Logout()
+        public void Test001_Should_Return_Success_On_Sync_Logout()
         {
-            TestOutputLogger.LogContext("TestScenario", "Logout");
+            TestOutputLogger.LogContext("TestScenario", "SyncLogout");
             try
             {
-                ContentstackClient client = Contentstack.Client;
+                ContentstackClient client = Contentstack.CreateAuthenticatedClient();
+                AssertLogger.IsNotNull(client.contentstackOptions.Authtoken, "AuthtokenBeforeLogout");
+
                 ContentstackResponse contentstackResponse = client.Logout();
                 string loginResponse = contentstackResponse.OpenResponse();
 
-                AssertLogger.IsNull(client.contentstackOptions.Authtoken, "Authtoken");
-                AssertLogger.IsNotNull(loginResponse, "loginResponse");
+                AssertLogger.IsNull(client.contentstackOptions.Authtoken, "AuthtokenAfterLogout");
+                AssertLogger.IsNotNull(loginResponse, "LogoutResponse");
             }
             catch (Exception e)
             {
                 AssertLogger.Fail(e.Message);
             }
         }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public async System.Threading.Tasks.Task Test002_Should_Return_Success_On_Async_Logout()
+        {
+            TestOutputLogger.LogContext("TestScenario", "AsyncLogout");
+            try
+            {
+                ContentstackClient client = Contentstack.CreateAuthenticatedClient();
+                AssertLogger.IsNotNull(client.contentstackOptions.Authtoken, "AuthtokenBeforeLogout");
+
+                ContentstackResponse contentstackResponse = await client.LogoutAsync();
+                string logoutResponse = contentstackResponse.OpenResponse();
+
+                AssertLogger.IsNull(client.contentstackOptions.Authtoken, "AuthtokenAfterLogout");
+                AssertLogger.IsNotNull(logoutResponse, "LogoutResponse");
+            }
+            catch (Exception e)
+            {
+                AssertLogger.Fail(e.Message);
+            }
+        }
+
+        [TestMethod]
+        [DoNotParallelize]
+        public void Test003_Should_Handle_Logout_When_Not_LoggedIn()
+        {
+            TestOutputLogger.LogContext("TestScenario", "LogoutWhenNotLoggedIn");
+            ContentstackClient client = CreateClientWithLogging();
+
+            AssertLogger.IsNull(client.contentstackOptions.Authtoken, "AuthtokenNotSet");
+
+            try
+            {
+                client.Logout();
+            }
+            catch (Exception e)
+            {
+                AssertLogger.IsTrue(
+                    e.Message.Contains("token") || e.Message.Contains("Authentication") || e.Message.Contains("not logged in"),
+                    "LogoutNotLoggedInError");
+            }
+        }
     }
 }
diff --git a/Contentstack.Management.Core/contentstack.management.core.csproj b/Contentstack.Management.Core/contentstack.management.core.csproj
index dbe8960..f422b69 100644
--- a/Contentstack.Management.Core/contentstack.management.core.csproj
+++ b/Contentstack.Management.Core/contentstack.management.core.csproj
@@ -3,11 +3,11 @@
   <!-- On non-Windows (e.g. macOS/Linux), build only netstandard2.0; .NET Framework (net471/net472) is Windows-only and reference assemblies are not available. -->
   <PropertyGroup Condition="'$(OS)' == 'Windows_NT'">
     <TargetFrameworks>netstandard2.0;net471;net472</TargetFrameworks>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(OS)' != 'Windows_NT'">
-    <TargetFrameworks>netstandard2.0</TargetFrameworks>
-  </PropertyGroup>
-  <PropertyGroup>
+    </PropertyGroup>
+    <PropertyGroup Condition="'$(OS)' != 'Windows_NT'">
+      <TargetFrameworks>netstandard2.0</TargetFrameworks>
+    </PropertyGroup>
+    <PropertyGroup>
     <LangVersion>8.0</LangVersion>
     <Nullable>enable</Nullable>
     <Title>Contentstack Management</Title>