title: "The underlying provider failed to Open" exception on IIS Local Machine using WEB API and Entity Framework Project
body: <p>I have a Web API 2 project which works perfectly with local IIS express, but when I deploy on my local machine IIS, I get the error below:</p>
  
  <pre><code>{
    "Message": "An error has occurred.",
    "ExceptionMessage": "The underlying provider failed on Open.",
    "ExceptionType": "System.Data.Entity.Core.EntityException",
    "StackTrace": "   at System.Data.Entity.Core.EntityClient.EntityConnection.Open()\r\n   at System.Data.Entity.Core.Objects.ObjectContext.EnsureConnection()\r\n   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)\r\n   at System.Data.Entity.Core.Objects.ObjectContext.&lt;&gt;c__DisplayClass49.&lt;ExecuteFunction&gt;b__47()\r\n   at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)\r\n   at System.Data.Entity.Core.Objects.ObjectContext.ExecuteFunction(String functionName, ObjectParameter[] parameters)\r\n   at ServiceDBUtility.FamLinkEntities.MBSP_INSERT_ERROR_LOG(String p_ID_USER, String p_ERROR_MSG, String p_ERROR_TRACE, String p_ERROR_TYPE, String p_REQUEST_URL, Nullable`1 p_ERROR_DATE)\r\n   at ServiceDBUtility.Repository.LogRepository.WriteLog(String p_ID_USER, String p_ERROR_MSG, String p_ERROR_TRACE, String p_ERROR_TYPE, String p_REQUEST_URL, Nullable`1 p_ERROR_DATE)\r\n   at ServiceDBUtility.CommonFunctions.WriteLog(String USER_ID, Exception Ex, String reqURL)\r\n   at ServiceDBUtility.CommonFunctions.ThrowException(Exception e, HttpRequestMessage request, String customErrorMessage)\r\n   at LoginService.Controllers.LoginController.Login()\r\n   at lambda_method(Closure , Object , Object[] )\r\n   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.&lt;&gt;c__DisplayClass10.&lt;GetExecutor&gt;b__9(Object instance, Object[] methodParameters)\r\n   at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Web.Http.Controllers.ApiControllerActionInvoker.&lt;InvokeActionAsyncCore&gt;d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Web.Http.Filters.ActionFilterAttribute.&lt;CallOnActionExecutedAsync&gt;d__5.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Web.Http.Filters.ActionFilterAttribute.&lt;CallOnActionExecutedAsync&gt;d__5.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Web.Http.Filters.ActionFilterAttribute.&lt;ExecuteActionFilterAsyncCore&gt;d__0.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Web.Http.Controllers.ActionFilterResult.&lt;ExecuteAsync&gt;d__2.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Web.Http.Dispatcher.HttpControllerDispatcher.&lt;SendAsync&gt;d__1.MoveNext()",
    "InnerException": {
      "Message": "An error has occurred.",
      "ExceptionMessage": "Login failed for user ''.",
      "ExceptionType": "System.Data.SqlClient.SqlException",
      "StackTrace": "   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal&amp; connection)\r\n   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal&amp; connection)\r\n   at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal&amp; connection)\r\n   at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)\r\n   at System.Data.SqlClient.SqlConnection.TryOpenInner(TaskCompletionSource`1 retry)\r\n   at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)\r\n   at System.Data.SqlClient.SqlConnection.Open()\r\n   at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.&lt;&gt;c__DisplayClass1.&lt;Execute&gt;b__0()\r\n   at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)\r\n   at System.Data.Entity.Core.EntityClient.EntityConnection.Open()"
    }
  }
  </code></pre>
  
  <p>Can someone provide insight into what might be causing this error?</p>