ASP.NET Virtual Path Maps To Another Application Which Is Not Allowed

Question

I have a website that was building without any issue on multiple servers.
But, when I copy/move it on the same machine from one folder to another folder: I started getting the error

The Virtual Path Maps To Another Application Which Is Not Allowed.

What am I doing wrong?

Answer 1

This isn't why your error happened but it may be useful to someone researching the problem who ends up here.

If your web app is running as an application within another IIS site (set via the IIS administration tool) and is attempting to reach resources of the other site by means such as HttpResponse.Redirect, make sure the project isn't set to use a separate IIS in Visual Studio. If it is, it may be firing up inside a different IIS than the rest of the site.