SYS. webforms. pagerequestmanagerservererrorexception: an unknown error occurred while processing

Recently, an Ajax control was used to automatically refresh some page data at regular intervals without screen refreshing.
SYS. webforms. pagerequestmanagerservererrorexception: an unknown error occurred while processing the request on the server. The status code returned from the server was: 500.
Several solutions are found online

Method 1:
Add this sentence to Web. config.Code, Do not verify the event data
<System. Web>
<Pages enableeventvalidation = "false"/>
</System. Web>
Problem: This code originally exists in my web. config, but my local computer and some computers won't see the above errors, but some computers will appear, depressed ......

Method 2:

Add enablepartialrendering = "false" to scriptmanager to display detailed error information.

As follows:
<Asp: scriptmanager id = "scriptmanager1" runat = "server" enablepartialrendering = "false"/>
Problem: This method will make the page have a screen flushing effect. I just want to solve the screen flushing problem, so it cannot solve my problem.

Method 3:
The general cause is that there are potential dangerous characters on the page. Add validaterequest = "false" to the header"

As follows:

<% @ Page Language = "C #" masterpagefile = "~ /Masterpages/companymanage. Master "autoeventwireup =" true "codefile =" companyintroedit. aspx. cs "inherits =" companyintroedit "Title =" untitled page "validaterequest =" false "%>

The last method is quite effective and has not been found yet.

Thank you !!!!