@samehmeh @lifeit
It sounds like something causing 500 Internal Server Error.
Error 500 that usually means something has triggered a PHP error, but errors are hidden on your server. To find out the cause of the error we have two choices:
Look at your server error logs and find the latest ‘fatal error’
Enable WP_DEBUG mode and view the page again
Enabling WP_DEBUG involves editing your wp-config.php file and changing, or adding if it’s not there:
define( 'WP_DEBUG', true );
When this is done, a more useful error message should be shown. Most of the time this contains the name of the plugin file and the line number causing the issue allowing you to act.
Once you have a useful error, if it’s not obvious whats causing it, post it here for us.