Hi All I have Windows 2003 Service SP2 with Exchange 2003 SP2, all windows updates installed. my problem is internal mail is missing (not listed in exchange manager queues) Also the mailbackup mailbox is not receiving mail. Outbound mail to one domain is queueing but staying active (no retry) but others are fine. Message tracking is saying the mail was sent to the MTA but nothing else (2 lines of text) We have also seen evernt messages for MTA Event Type:WarningEvent Source:MSExchangeMTAEvent Category:X.400 Service Event ID:290 and Event Type:WarningEvent Source:MSExchangeTransportEvent Category:Routing Engine/Service Event ID:956 All Outlooks are connected fine.