I recently installed Server 8.04 and my subscriptions stopped working. I also noticed that my Backgrounder Reap extracts were running constantly. I killed it a few times and did a start/stop and reboot. Once I even let it run for 12hrs before killing it.
Finally I deleted all my schedules and subscriptions and started over to run one at a time. The first one I ran I got a failure stating "Must issue a STARTTLS command first". After a search for that turned up nothing I went back into the Server Config and saw an unchecked check box for "Enable TLS". I can't remember if it was there before but I can't find any information about it either.
I figured I'd give it a go and enable it. When I restarted the server I got a email letting me know it started, I hadn't realized that these had stopped also, and now my subscriptions work.