Error message 401.2.: Unauthorized: Logon failed due to server configuration. When application deployed

Question

I have an asp.net 4.0 application that works fine running under cassini but when i deploy to IIS i get the above error. It is running under the Default App pool which a numb

Answer 1

I was also getting this error trying to run an existing ASP.NET WebForms application under IIS Express (but this probably also applies to IIS).

The application was configured in the applicationhost.config to use the Clr4IntegratedAppPool application pool. Changing the applicationPool attribute to Clr4ClassicAppPool solved the problem for me.