I have just deployed my asp.net mvc-2 website to a server (using dotnetpanel). But getting this error
A default document is not configured for the requested
In my case, I had to install the Microsoft.Owin.Host.SystemWeb package.
Microsoft.Owin.Host.SystemWeb
I was getting the same message as you did, but then noticed I couldn't even hit a breakpoint in Startup.cs which then let me to this SO thread.
Startup.cs