Why am I getting the message "The specified request cannot be executed from current Application Pool"?

Question

Quite not sure why I see this error. I navigate to my Login View like so http://test.staging.com/mywebsite/Login

My Login view was just redone using MVC but I have seen this same error message going to an aspx page as well...

If I use http I get the error message The specified request cannot be executed from current Application Pool. If I use https://test.staging.com/mywebsite/Login, I'm good. If I don't specify a protocol, test.staging.com/mywebsite/Login, I get the error as well

Is there an error happening under the covers and my custom error page can't be shown like discussed here?

What are some other causes of this error?

Answer 1

That usually means your custom errors are configured to run as a different AppPool.

You can read more at MSDN. (See section "Using Custom Errors from Another Application Pool").

There are two ways to correct this behavior. The first is possibly not one that you are interested in because it would require you to change your current architecture and run both sites in the same application pool (such as share the same worker process memory space). To do this, simply move the /errors virtual directory to run in the same application pool as the site for which it serves the custom error.

The second way is to make use of a registry key provided by IIS 6.0. This registry key makes sure IIS 6.0 does not check the metadata during the execution of the custom error and therefore allowing this to work.

See the article for information on the registry key fix.

It may also mean that you are using something along the lines of Server.Transfer to a page that is in a different AppPool.

Answer 2

It could be because you're using different versions of ASP.NET for one or many apps in the pool.

1. Make sure all apps in the pool use the same version of ASP (e.g. ASP 2.0.50727)
2. If you just added a new app, try changing the app momentarily to a different version of ASP, then back to same version. I experienced an issue where the displayed version was correct, but under the hood, a different version was used!
3. Check your event log, under Application, to get more details about the error.