I have just setup a new domain, with 2008 R2 DC and a separate 2010 exhchange server. The existing PCs were removed form the old domain and joined to the new. Everything going ok so far.
I had a complaint from a user that some emails which were destined for internal users were not arriving. When I went to investigate, sure enough there were 17 internal messages waiting in the queue called mailbox database 0061177055 for MAPI delivery. There's nothing in the last error column. When I ran the mailflow troubleshooter, it says that there are no mail queues backing up even though the messages are in there. Then 20 minutes later tey will have been delivered successfully.
What's going on here?