Can't login via SSH after upgrading from stock firmware

Help! I've taken the AsusWRT-Merlin plunge and everything seems to have gone fine.

I can login to the web interface using my username and password but can't login via SSH with the same credentials! I have tried disabling and re-enabling the SSH in settings but that didn't work.

I'm not sure what else to do. If anybody can give some insight or suggestions, I would really appreciate it.

Thanks