Server Error in '/' Application.

This operation requires the page to be asynchronous (the Async attribute must be set to true).

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: This operation requires the page to be asynchronous (the Async attribute must be set to true).

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: This operation requires the page to be asynchronous (the Async attribute must be set to true).]
   System.Web.UI.Page.RegisterAsyncTask(PageAsyncTask task) +511
   MasterPage.Page_Load(Object sender, EventArgs e) +168
   System.Web.UI.Control.OnLoad(EventArgs e) +79
   System.Web.UI.Control.LoadRecursive() +130
   System.Web.UI.Control.LoadRecursive() +200
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2818


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3930.0