Server Error in '/' Application.

Only one instance of a ScriptManager can be added to the page.

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: Only one instance of a ScriptManager can be added to the page.

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: Only one instance of a ScriptManager can be added to the page.]
   System.Web.UI.ScriptManager.OnInit(EventArgs e) +453333
   System.Web.UI.Control.InitRecursive(Control namingContainer) +142
   System.Web.UI.Control.InitRecursive(Control namingContainer) +318
   System.Web.UI.Control.InitRecursive(Control namingContainer) +318
   System.Web.UI.Control.InitRecursive(Control namingContainer) +318
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +416


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4700.0