Chris, Your best bet to tracking down what's going on is to get on the phone with a mail administrator on the other end to see if they can reproduce the 'no-show' scenario. Have them create a new message to the user who is not receiving mail consistently. Make sure they are using the correct smtp address. Make sure they are NOT receiving any NDR's. Ask them to send a copy of the message to themselves and to you, as well as to the user who first brought this to your attention. Ask them if they can check out the client machine of the supposed sender. Make sure you are not blocking/filtering out any part of the sender's smtp address. Let me know if you make any progress with this. Good luck! Karen -----Original Message----- From: Chris McNally [mailto:cmcnally@xxxxxxxxxxxxxxxxxxx] Sent: Tuesday, January 21, 2003 2:41 PM To: [ExchangeList] Subject: RE: [exchangelist] RE: Not all mail coming in. http://www.MSExchange.org/ This is a multi-part message in MIME format.