The cause of this error may stem from the server and can also come from the user side.(Usually due to syntax errors in your .htaccess file or CHMOD )
This error is common in 1 Some servers do not allow setting permissions for folders CHMOD 777 mode, aims to protect the back-end part of ban.Do on localhost few people thought about security for the webserver configured so rare this error.
When encountering this error : choose File Mananger or use an FTP program on your host and back to the folders CHMOD is 755 while the file is 644, or try to rename / delete the .htaccess file in the host, then try to access it again.
After making the deal on condition remains, you can contact directly with suppliers hosting to help overcome.
Error 500 Internal Server Error,