ASP.Net when post back get The specified URL cannot be found

Question

When clicking the save button on a asp.net web form page, I get the following immediately:

The specified URL cannot be found

This does not happen when I try this using a browser on the web server.

Has anyone run across this problem before? Is this some kind of security issue?

Answer 1

Could you provide a bit more information?
This could be caused by a lot of things:

• Is IIS configured properly for the site? Authentication, host header settings?
• Did you try http://localhost/.. on the webserver or did you use the webserver's host name?
• Are you redirecting the user? What are you doing in the button event?
• Are you using URL routing? Or a handler that might be causing problems?
• What version of the .NET framework are you running? 1.1 / 2.0 / higher?
• Does the page include javascript that could cause unexpected results?
• Checked for crazy stuff in your web.config?

Sometimes it's a good idea to take a step back and create a new ASPX page and test if that one works. Start from a predictable scenario and move towards your current scenario in baby steps.

Answer 2

More information. I tried a test page that included all of the form fields and a button that didn't do anything but write to a log4net log. Same problem on the button click. This is just weird.

Answer 3

Found the solution to this!!! Turns out the firewall was blocking request that had more then 40 parameters in the query string.