Hi When mail sent to a specific user it stays in eth queue and gives the following message; This is an automatically generated Delivery Status Notification. THIS IS A WARNING MESSAGE ONLY. YOU DO NOT NEED TO RESEND YOUR MESSAGE. Delivery to the following recipients has been delayed. user@somedomian.com Finally it fails with following message; Your message did not reach some or all of the intended recipients. Subject: <subject> Sent: 13/10/2010 20:16 The following recipient(s) could not be reached: <Recipient Name> on 17/10/2010 20:18 Could not deliver the message in the time limit specified. Please retry or contact your administrator. <ourdomain.com #4.4.7> When I click on the relevant queue in exchange it says 'An SMTP protocol error occurred'. What is the problem and how can I fix it? Thanks Regards

Hi Which version of Exchange are you referring to? I would start verbose logging on the receive connector and check the logs Is this only happening with one user? Does his mailbox works? Can you logon to OWA and Outlook without any issues?Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

Hi Exchange 2003 as part of sbs 2003 standard. All mail seems to be going out fine except to this client who are based in Qatar and one other client. Thanks Regards

Try to logon OWA and see if everything is OKJonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

Hi OWA works fine. Problem is really mail not getting out to a couple of external contacts rest seems OK so far. Thanks Regards

Ok, check their email address and start verbose logging for the send connector and send a test mail then check the logfile Double check spelling, format etc Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

That sounds a lot like there's an SMTP proxy along the path http://support.microsoft.com/kb/320027. I would turn up protocol logging and take a look.

Hi I did a telnet to the mail server of one of the recipients we were having problem with and it returned; 554 try again later Connection to host lost. Thanks Regards

Hi I did a telnet to the mail server of one of the recipients we were having problem with and it returned; 554 try again later Connection to host lost. Thanks Regards This might not mean that there is a problem. A lot of companies with hosted message hygiene block all SMTP traffic from the internet excpet traffic from the provider. You might want to run the SMTPDiag tool. It will take exchange out of the picture and just test message delivery on an SMTP basis. http://www.microsoft.com/downloads/en/details.aspx?familyid=bc1881c7-925d-4a29-bd42-71e8563c80a9&displaylang=en Tim Harrington - Catapult Systems - http://HowDoUC.blogspot.com

I suggest you refer to the following article to recreate the mail profile to check the result. http://support.microsoft.com/kb/829918 For more information, please refer to the following thread: http://social.technet.microsoft.com/Forums/en/exchangesvradmin/thread/0e0ce26a-9fe8-4f30-abe1-b619d854e8f5 However, if the issue persists, please check whether there is any error message in Event Log and post the message tracking log here for research. Thanks.Novak Wu-MSFT