I've got about a dozen servers that I log into via an authorised ssh key, and up until today it was working fine. Today, one of those servers refuses to accept my key - it accepts a root key and my passphrase, just not my key. Nothing has changed in the ssh configs, and the key is still in my authorized_keys. Any idea why it's stopped working?
.ssh directory chmod 700?.ssh/authorized_keys chmod 600?owned by you?
If the server sshd_config wasn't changed and the other keys work, I would suspect something happened to the directory or permissions that contain your key.