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.InvalidOperationException: Collection was modified; enumeration operation may not execute.
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:
[InvalidOperationException: Collection was modified; enumeration operation may not execute.] System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource) +60 System.Collections.Generic.Enumerator.MoveNextRare() +14521243 System.Linq.Enumerable.FirstOrDefault(IEnumerable`1 source, Func`2 predicate) +202 ptaWebApp.SessionContextList.Add(SessionContext session) in C:\Users\froschl\source\repos\ptais\MainV2\ptais-projects\ptaWebApp\classes\SessionContextList.cs:42 System.Web.SessionState.SessionStateModule.CompleteAcquireState() +375 System.Web.SessionState.SessionStateModule.BeginAcquireState(Object source, EventArgs e, AsyncCallback cb, Object extraData) +1257 System.Web.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +703 System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +75 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +158