I have just started using UltiDev but am having issues:

I have a very simple ASP.NET (4.0) page that I am serving up with UltiDev Web Server Pro.
When I click a button I do a

Response.Redirect("MainPage.aspx")

All works fine until I leave the page in my browser for some time (I can't tell you a specific amount of time but it is a few minutes). I then click on the button and after about a minute or more of waiting for a page load I get:

Firefox:

'The connection to the server was reset while the page was loading.'

IE9:

'Internet Explorer cannot display the webpage'

If I refresh everything works fine again until a period of inactivity - any suggestions?

I tried this in IIS and that does not seem to have the same issue.

Can someone give some advice as to what is happening here?

Thanks