IMA-USA is a retailer in relic arms and militaria here in PA. Its actually quite well known if you are into that sort of thing.
So I have to look at the Dovecot IMAP server to see why its hung, and of course the log files are the first place to look. This is what I see:
Sep 28..... CD21540E42D6: from=<BJ4HBDVGNPLCU7OC8M3S6OOHLARG3JHCUFCKROC2IFED6PNEHN98RHD05LJB3CO@bounce.ima-usa.com>, size=10296
Asshats are using a fake bounce address so when they spam you, the bounced email dies in your local queue. This is how 3rd world Nigerian 401 scammers operate.
nslookup bounce.ima-usa.com
Non-authoritative answer:
*** Can't find bounce.ima-usa.com: No answer
Dirtbags.