For those who get this error:
Internal Server Error
The server encountered an internal error or misconfiguration and was unable to complete your request. Please contact the server administrator, firstname.lastname@example.org and inform them of the time the error occurred, and anything you might have done that may have caused the error. More information about this error may be available in the server error log. Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.
Look at your Configure PHP and SuExec, under the whm of your cpanel.
Then pay with the php handler, lswitch from dso, cgi... and apply and test. when u find one that works, leave it like this.