Restart Web Server and mySQL Server
If your web server and/or mySQL server crashes and becomes unresponsive or very slow to respond or displays a weird error, then you may need to restart the server. Typically you can do this via a web-based control panel like cPanel. If you have SSH access but no cPanel or other means to restart, then you can restart via SSH as follows:
Restart Web Server
/sbin/service httpd restart
Restart mySQL Server
Otherwise, you need to contact your web host to have them restart those affected services.