500 Errors displaying instead of detailed error messages

On Windows 2008 (DotNetPanel) hosting, I get a 500 error page and the detailed error is not shown.  How to I display the error?

Edit the web.config file in your DOMAIN/wwwroot folder.

After  </handlers>  press enter and add the following line

<httpErrors errorMode="Detailed"/>

it should now look like:

<httpErrors errorMode="Detailed"/>

Save this file, this will now show 500 errors.