SMTP from wiki.xmpp.org fails

When trying to send a password reset email, the SMTP connection aborts due to an incorrectly set hostname in HELO ("localhost"?):

> Error sending mail: Failed to add recipient: *censored@address* [SMTP: Invalid response code received from server (code: 504, response: 5.5.2 <localhost>: Helo command rejected: need fully-qualified hostname)]
