If you previously pulled from code.monotone.ca, you’ll probably get a SERVER IDENTIFICATION warning the next time you sync with it. The problem was that I issued keys with wrong key names previously (which pointed to the temporary DNS) and I had to drop and re-add new keys with the proper DNS name.
Please execute therefor
$ mtn unset known-servers mtn://code.monotone.ca/<project-name>
e.g. for the monotone project
$ mtn unset known-servers mtn://code.monotone.ca/monotone
on the particular local databases and you’ll be able to pull / sync again.
Sorry for the inconvenience.