We are getting an error "The page was not displayed because the request entity is too large" on our new web server.
After much testing we have found a way to reproduce the error with 100% certainty. The tests were run with the latest version of Internet Explorer as well as Firefox (both running on Windows 7).
The error only happens when the following three conditions are met at the same time:
1. The error only shows up if the page is viewed as HTTPS (SSL)
2. The error only shows up if the page is above a certain size. If the test page contains a textbox with a string of around 40Kb size the error never happens. If the test page contains a textbox with a string of around 50Kb size the error always happens.
3. The error only shows up if the user waits at least 60 seconds before doing a postback.
Windows server 2008 R2 (64 bit) running IIS 7.5.
Website ASP.NET 3.5
We have changing the uploadreadaheadsize in the following way: "cscript adsutil.vbs set w3svc/1/uploadreadaheadsize 204800" but it has not fixed the issue. The applicationHost.config under 'C:\Windows\System32\inetsrv\config' shows <serverRuntime uploadReadAheadSize="204800" /> so the change is reflected there.
The default size for UploadReadAheadSize is 49152 which explains perfectly why we are seeing the error when the page size is 50Kb and why we are not seeing the error when the page size is 40Kb. It is as if the change to the UploadReadAheadSize never took effect.
I'm starting to think this might be an IIS 7.5 issue and that the above change to UploadReadAheadSize only affects IIS 6.0. However, in that case I'm not sure how to change UploadReadAheadSize for IIS 7.5.
Thanks for your help!