For the 3rd or 4th time this year I'm having a problem with exim not delivering emails - and backing up in the que some this time for 7 days. The exim message I get is a warning that "the email has not been delivered to 1 or more of its recipients for 48 hours". The first time it happened the iptables apparently got misconfigured and support had to fix. When the server went down a couple of weeks back - support "forced the emails to be delivered and then restarted exim". Well, for no apparent reason the problem has reappeared. Support just forced sending again and restart exim. I need to figure out why this is happening as the only thing I see I can do now is change the MX of my client sites to google apps or check the exim que a few times a day.

Any suggestions would be REALLY appreciated.