Doing some investigation, I discovered that it's not sending an initial "+OK POP3 Ready" response. Without the clients getting any "+OK" response, they think the connection is still pending and they wait to send the USER command.
Good catch. When I was messing with the code between MIS and MIS2 I
apparently accidentally deleted the welcome message. I've added it back in
the latest prealpha but I haven't tested it yet.
I made a note to test it more thoroughly this weekend but today's prealpha
will have the change in it too.
--- Mystic BBS v1.12 A37 2017/12/05 (Windows/32)
* Origin: Sector 7 [Mystic BBS WHQ] (21:1/108)