When i am working on my website sometimes it is throwing the following error message in chrome browser console window.

Uncaught Sys.WebForms.PageRequestManagerParserErrorException: Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.
Details: Error parsing near 'Denied'.

Why it is giving this error, and how could we solve this.