ASP.NET web.config error

My ASP.NET web application works fine in VS. But when I try and deploy it on my webserver I get an error screen:

HTTP Error 500.19 - Internal Server Error. The requested page cannot be accessed because the related configuration data for the page is invalid.

Error Code 0x8007000d 
Config Error
Config File \\?\C:\Domains\leas****mail.com\web.config 

Config Source
-1:
0:

Any idea how I can debug this. Normally it would where in the web.config the issue is, but not in this case. I ran the file through an xml validator and there were no issues detected.

Thanks

You are using a component that defines a new section in web.config. And that component is not installed on your server. I have this problem often with the URL Rewrite for IIS module (from here) or with the .NET Chart Controls (from here) for example.

Check your web.config section by section. You'll spot the culprit...