Right, so, since today, when I click on messages, read messages, I get a database error ("if you see this report this to an administrator) and only two messages on the list below. I haven't deleted my inbox for the past 5 years. Also I can't read those two messages as well.
Hmm, this is a fun bug. Apparently threads that contain posts by a member of the new AGS Project Admin team weren't working properly. I've temporarily fixed this, at the expense of some user titles having gone a bit odd. It'll be fixed properly soon!