Check your sshd.conf, you may of set it to only accept calls from a specific interface address such as this
And if that is so, it'll refuse to listen to any other IPs.
There is most likely other things but this is the first thing that sprung to mind as I setup my sshd again the other day. Good luck!.
Also what command are you using to ssh in, and what client (if any). Could it have saved the wrong address? Are you pointing to a hostname, or the actual IP address when dialing in?.