public key refused, works on other servers

Hello there,
 I've been using LP for a year or so, but tonight the servers don't recognize my private key.

- "bzr lp-login invernizzi" works without issues.
- a push gives "Permission denied (publickey)."
- ssh -v <email address hidden>

debug1: ssh_rsa_verify: signature correct
debug1: Enabling compression at level 6.
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Offering public key: /home/luca/.ssh/id_rsa
debug1: Authentications that can continue: publickey
debug1: Trying private key: /home/luca/.ssh/identity
debug1: Trying private key: /home/luca/.ssh/id_dsa
debug1: No more authentication methods to try.
Permission denied (publickey).

But ssh on another server (with the same key) goes fine:

debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey,password
debug1: Next authentication method: publickey
debug1: Offering public key: /home/luca/.ssh/id_rsa
debug1: Server accepts key: pkalg ssh-rsa blen 533
debug1: Enabling compression at level 6.
debug1: Authentication succeeded (publickey).

I'm at a loss here. Any suggestions?