I added a new user to one of our servers, but can't log in to it via putty. The error message is "Server refused our key", and from putty, "Disconnected: no supported authentication methods available (server sent: public key). Putty is set up to use a putty private key (.ppk file) to access the server. I looked in /etc/ssh/sshd_config, but didn't find anything specifying the user. Any ideas?