hg push always asks for http authorization, even with ssh

After doing some first hg push, I edited a few more files and hg pushed once more:
{{{
crea@alpha:~/devel/moneyguru$ hg push
Enter passphrase for key '/home/crea/.ssh/id_rsa':
pushing to ssh://hg@bitbucket.org/some/repo
pushing subrepo lib
searching for changes
http authorization required
realm: Bitbucket.org HTTP
user: crea
password:
abort: authorization failed
}}}
But now, there is always this "http authorization required" thing, even when I do not use hg via HTTPS.
What's wrong here?

(Note: my first commit/push was with an https repository, there it worked without problems).