Hi all. I installed zimbra a couple weeks ago and the install went very well. I enjoyed zimbra for a couple days and then started noticing that messages were pilling up in the deferred queue and I couldn't figure out why. I am getting messages in the log like the following:

Sep 26 04:07:45 mythtv postfix/lmtp[9754]: 6335B16EBAE: to=<pta-amidala@psaconsultants.com>, relay=none, delay=300, status=deferred (connect to mythtv.psaconsultants.com[]: read timeout)

The problem is I can't figure out what that means. To solve the problem temporarily, I restart zimbra and then flush the queue and all the messages deliver. Everything works fine for a while and then things start to pile up in the deferred queue again.

I've searched the forums and it looks like there are some issues with permissions and the queue so I tried to run zmfixperms but it didn't fix the problem. I've also read that the system has to be up to date but it doesn't mention which packages. I've tried to run yum upgrade on the system but it fails due to dependecies so if I knew which packages to upgrade, I could try that.

Anyway, any and all pointers and help would be appreciated. My setup is:

Fedora Core 5 (slightly out of date)
Zimbra 4.0.1_GA_324

I will be happy to provide any other information/logs/etc.