Running 2 servers on Ubuntu 8.04, one runs moodle, the other zimbra. We've just upgraded to Zimbra 6.07 and it's started bouncing the forum digests from the Moodle server on the same network (never a problem before). I've tried whitelisting the domain the moodle.local and also on the zimbra server by editing /opt/zimbra/conf/ but no joy.

excerpt from mail log on Moodle server:

Sep 20 20:00:01 moodle postfix/local[3002]: C14B41401B7: to=<>, relay=local, delay=0.04, delays=0.02/0.01/0/0.01, dsn=5.1.1, status=bounced (unknown user: "x.bell100")
Sep 20 20:00:01 moodle postfix/cleanup[3000]: C60631402D6: message-id=<20100920190001.C60631402D6@moodle.local>

Any advice welcome!