We have seen spool backups happening more often for the last few months, restarting the smarter mail services and local DNS server seems to flush things through. Seems to happen about once a week, sometimes more.
I realize this can indicate many different things (DNS issues, slow RBL, etc). That said, there are a few similar threads in the forums.
It looks like switching to Google DNS has been a common troubleshooting step, however in production that could wreak havoc with some RBLs so its not a long term solution.
Has anyone else been seeing an increase in this type of issue on SmarterMail v13? We are running the latest (13.2.5511)
I'm not positive if the symptoms coincide with upgrading to 13.x, but that's a possibility.
Thanks in advance