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
This issue for me was caused by a database mapping error.
I attempted to use a select() call on a datasource with errors in the code behind. My controls were within an update panel and the actual cause was hidden.
Usually, if you can temporarily remove the update panel, asp.net will return a more useful error message.