If authorized_keys exists, but has chmod 000, or .ssh has chmod 000 or 600, or for other reason it can not be read by server, then there is little clue, in the logs, what is going on.
Just:
debug1: trying public key file /home/userfoo/.ssh/authorized_keys
debug1: restore_uid: 0/0
Admin should be informed that there was some problem accessing authorized_keys (other then not-existing file).
If authorized_keys exists, but has chmod 000, or .ssh has chmod 000 or 600, or for other reason it can not be read by server, then there is little clue, in the logs, what is going on.
Just: .ssh/authorized _keys
debug1: trying public key file /home/userfoo/
debug1: restore_uid: 0/0
Admin should be informed that there was some problem accessing authorized_keys (other then not-existing file).