Deploying website: 500 - Internal server error

Question

I am trying to deploy an ASP.NET application. I have deployed the site to IIS, but when visiting it with the browser, it shows me this:

Server Error

Answer 1

In my case, I put a mistake in my web.config file. The application key somehow was put under the tag. But I wonder why it doesn't display a configuration error. The error 500 is too generic for investigating the problem.