3 FE Win 2003 with Ex 2003 SP2 + 2 x 2 active/passive BE Win 2003 with Ex 2003 SP1
After updatering FE servers and one BE cluster, OWA can't reach mailboxes on the updated BE.
Tried to update the one BE cluster to SP2, so FE and BE was the same, but no result.
The one BE cluster not updated, and still running SP1, is running smoothly through FE OWA.
Also trouble sending mails from one BE to the other.