Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server."

Question

I have couple of update panels and jquery tabs on page. And also I am loading couple user controls on update panels. After user waited for couple of minutes (not checked the

Answer 1

Be sure to put tilde and forward slash(~/) when CDN is the root directory. I think it's an issue in IIS

Answer 2

Some times due to some code you get HTML tags in a text filed, like I was replacing some characters with new line BR tag of HTML and by mistake I also replaced it in the text that was supposed to be displayed in a Multiline text box so my multiline text box had a new line HTML tag BR in it coming dynamically due to my string replace function and I started getting this JavaScript error and as this HTML code was displayed in a text box that was in an update panel I start getting this error so I made the correction and all was fine. So before copying pasting anything please look at your code and see that all tag are closed proper and no irrelevant code data is coming to text boxes or Drop down lists. This error always come due to ill formed tags and irrelevant data.

Answer 3

I have got the same issue, here I give my problem and my solution hoping this would help someone:

Following other people recommendation I went to the log of the server (Windows Server 2012 in my case) in :

Control Panel -> Administrative Tools -> Event Viewer

Then in the left side:

Windows Logs -> Application:

In the warnings I found the message from my site and in my case it was due to a null reference:

*Exception type: NullReferenceException 
Exception message: Object reference not set to an instance of an object.*

And checking at the function described in the log I found a non initialized object and that was it.

So it could be a null reference exception in the code. Hope someone find this useful, greetings.

Answer 4

I got this error when I had ModalPopupExtender in the update panel... deubbing my code I found that the above error is caused because of updatepanel updatemode is conditional... so i change it to always then problem is solved.

Answer 5

answer for me was to fix a gridview control which contained a template field that had a dropdownlist which was loaded with a monstrous amount of selectable items- i replaced the DDL with a label field whose data is generated from a function. (i was originally going to allow gridview editing, but have switched to allowing edits on a separate panel displaying the DDL for that field for just that record). hope this might help someone.

Answer 6

Had this problem when using AsyncFileUploader in an iFrame. Error came when using firefox. Worked in chrome just fine. It seemed like either the parent page or iframe page was loading out of sync and the parent page could not find the controls on the iframe page. Added a simple javascript alert to say that the file was uploaded. This gave the controls enough time to load and since the controls were available, everything loaded without an error.