There are a few different ways to restart SSHD remotely.
You will need root access in order to do this.
1) /etc/init.d/sshd restart
2) kill `cat /var/run/sshd.pid` && /usr/sbin/sshd

It is a good idea to disable root login for security purposes and use your login name and use sudo to get root privileges.
First of all, make sure you have your own login name and you can get root privileges by using sudo.
So, open up /etc/ssh/sshd_config and comment out
AllowUsers root
so it will look like:
#AllowUsers admin
You [...]