According to the developer of an HTTP debugging tool, Set-Cookie from aus3.mozilla.org specifies domain=aus2.mozilla.org. https://twitter.com/ericlaw/status/304319509743943680
Since this hasn't been working in a very long time, do we even still need the cookie? To fix: edit xml/inc/config-dist.php and update COOKIE_DOMAIN to 'aus3.mozilla.org'.
You need to log in before you can comment on or make changes to this bug.