Sysadminman VPSs come with a small utility called denyhosts installed. This monitors for people trying to connect to your VPS via SSH and if too many invalid login attempts are detected then the IP address is blocked.
To prevent this happening to your IP address you can add it to /etc/hosts.allow.
For instance if your IP adress is 126.96.36.199 then add it to the bottom of the /etc/hosts.allow file like this –
# hosts.allow This file describes the names of the hosts which are
# allowed to use the local INET services, as decided
# by the '/usr/sbin/tcpd' server.