Updated from GroupWise 7.0.3 to 8.0.0 about 45 days ago. Everything went great, no issues.

Updated from NWSP7 to SP8 Sunday. Again, everything seemed to be fine, except starting Tuesday I was getting more and more users getting undeliverable e-mail messages. They get a Send Failure: 550 Host unknown.

Tuesday it was maybe 10% of outgoing e-mails. Wed it's maybe 30% today its close to 50% getting this error. I'm not liking this progression.

Incoming e-mail is fine. Internet is fine (I can browse to all these failed domains, and I can ping them). No changes to our firewall or any sort of routing tables have happened. Those two changes are the only changes I've
made in the last 6 months.

I updated the DNS poisioning patch this afternoon and rebooted the server but it didn't help.

I'm going to be updating eDir this evening, but I don't think that's the cause. What's going on?

Any gueses?
Thanks in advance!