Recipient's mailbox is full, message returned to sender. (#5.2.2)

Mailbox needs a spring clean

hmmmm will get them to take a look at that.

Sorry about that, it looks like a setting was changed on the mailbox (it's normally unlimited). I did some archiving this morning to make more room, so it's been working again for about 6 hours, and will have the setting changed back to unlimited in the morning.