JavaScript runtime error Sys.WebForms.PageRequestManagerServerErrorException - Value cannot be null.

Environment

Product	Progress® Telerik® Reporting
Report Viewer	ASP.NET Web Forms Report Viewer

Relates to the Legacy Report Viewer

Description

The error is thrown when testing a Web Application in browser, run from Visual Studio 2013+.

Error Message

0x800a139e - JavaScript runtime error: Sys.WebForms.PageRequestManagerServerErrorException: Value cannot be null.  

Possible Cause

Such error can occur if the Web application is Ajaxified.

Solution 

BrowserLink is introduced in Visual Studio 2013. It can intersect AJAX calls, resulting in a JavaScript runtime error.

To test the application you can switch off BrowserLink from Visual Studio settings.

See Also

Using Browser Link in Visual Studio 2013 (source www.asp.net).