If you happen to mess up your ssh configuration some how you can reset the ssh config from Cpanel then restart your machine via ssh by using following command
If you cannot reboot your server manually, you can restart it by requesting a power cycle.
1) Log in to your Account Manager ( cpanel/whm ).
2) Click Servers.
3) Next to the server you want to use, click Manage.
4) Click Power.
5) Click Restart.