I am running two small lists and at least twice a week the mass mailing stops with items in the queue. The one that is blocking says 100% complete, but it never removes it from the queue and none of the messages after that are sent.
Any error logs associated with the problem?
No. The log mostly has:
Fri May 1 11:45:02 2015] mail.cgi: defined(@array) is deprecated at plugins/bridge line 1322, line 1.
[Fri May 1 11:45:02 2015] mail.cgi: (Maybe you should just omit the defined()?)
Then it logged when I forced the queue to restart by deleting the completed head element:
[Sun May 3 23:26:29 2015] mail.cgi: restart_with set to: 20150502210004.20206759_at_sacredstatus.net at DADA/Mail/Send.pm line 1069.
[Sun May 3 23:26:29 2015] mail.cgi: Reloading message... (4784) at DADA/Mail/MailOut.pm line 1928.
[Sun May 3 23:26:30 2015] mail.cgi: returning message firstname.lastname@example.org at DADA/Mail/MailOut.pm line 2751.
The only other log entry I see is [Sat May 2 12:55:05 2015] mail.cgi: Given an invalid email to create a redirect from, '#digest_20150501224508' - skipping! at DADA/Mail/Send.pm line 2340.
It seems to stop after a digest is sent out.