This morning, SSH was working fine. Now, it gives me "FATAL ERROR: Server unexpectedly closed network connection."
It seems like putty is not finding the SSH server. Regular telnet works fine.
I'd double check and see if for some reason a firewall is blocking your connecting. If that's not the case you should contact support, somehting probably went wonky with the ssh service.
I had that happen to me when my IP address (i.e. me) has too many failed login attempts. A note to support cleared it up.