I'm using DNN 5.5.0 and RadAjaxManager.
If I'm active within the web page everything works fine. However if I leave the page for longer than 2 minutes my AJAX requests timeout (PageRequestManagerTimeoutException). From then the page is basically broken and I have to reload the page to get it going again. My session timeout is definitely 20 minutes and I would expect to be redirected to the Login page when the session timeout occurs.I can only think this is somehow related to AsynchTimeout of 90s however if I disable AJAX I still get a page timeout. Setting AsynchTimeout to 600s has no effect. I'm pretty confident this is not on the server-side as I don't get to my breakpoint in the PageInit when returning after inactivity.
What could cause POST back requests to get lost between server/client when returning to an ASP.NET page due to inactivity. At this stage I'm developing in a test environment on Windows 7 and SQL Server Express 2008.