Session state has created a session id, but cannot save it because the response was already flushed by the application.

Server Error in '/fos' Application.

Session state has created a session id, but cannot save it because the response was already flushed by the application.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Session state has created a session id, but cannot save it because the response was already flushed by the application.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace: 


[HttpException (0x80004005): Session state has created a session id, but cannot save it because the response was already flushed by the application.]
   System.Web.SessionState.SessionIDManager.SaveSessionID(HttpContext context, String id, Boolean& redirected, Boolean& cookieAdded) +4321688
   System.Web.SessionState.SessionStateModule.CreateSessionId() +88
   System.Web.SessionState.SessionStateModule.DelayedGetSessionId() +103
   System.Web.SessionState.SessionStateModule.OnReleaseState(Object source, EventArgs eventArgs) +788
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +139
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +195
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +88

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3163.0