I'am using Debian Jessie.
I changed PermitRootLogin from yes to no in this file /etc/ssh/sshd_config , I saved but I forgot to create another super user account !! Now I'am logout and I can't access to my server as a Sudo because I can't edit this file from my other account :(
Help !
If you login via SSH as a normal user then do su root it will allow you to change user to root user.
You will of course need your root password. then add a new sudo user or whatever, you will have full root access.