Running Exchange 2007 SP2, Outlook 2007 SP2. One of my users is having problem sending emails to user@contoso.com. The NDR is "None of your email accounts could send to this recipient". Other users don't have this problem, and the user could send to the recipient a few days ago ok. I ran message tracking on our Hub Transport server, and there is no mention of my user trying to send to user@contoso.com, so it looks like the message is not even getting to Exchange, seems to be Outlook blocking it? Have send KB here, but doesn't apply: http://support.microsoft.com/kb/872896 Any ideas?

On Sat, 12 Mar 2011 16:45:40 +0000, Pancamo wrote: >Running Exchange 2007 SP2, Outlook 2007 SP2. One of my users is having problem sending emails to user@contoso.com. The NDR is "None of your email accounts could send to this recipient". Other users don't have this problem, and the user could send to the recipient a few days ago ok. I ran message tracking on our Hub Transport server, and there is no mention of my user trying to send to user@contoso.com, so it looks like the message is not even getting to Exchange, seems to be Outlook blocking it? Have send KB here, but doesn't apply: http://support.microsoft.com/kb/872896 Any ideas? OPen the NDR and click the "Resend" button. Double-click the address in the "To:" header and see what the address type is. If the address is in a domain outside your organization the type should be SMTP. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Thanks Richard. Do you know why there is no mention of my user attempting to send to user@contoso.com in the Hub Transport logs?

On Sun, 13 Mar 2011 17:43:52 +0000, Pancamo wrote: >Do you know why there is no mention of my user attempting to send to user@contoso.com in the Hub Transport logs? If the address type isn't one that Exchange knows how to route I wouldn't ecpect it to get much further than the mailbox server role. --- Rich Matheisen MCSE+I, Exchange MVP --- Rich Matheisen MCSE+I, Exchange MVP

Does it fail if you try to send using OWA?James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

I think OWA should be ok. Outlook 2007 and Outlook 2003 maintain a list of "allowed" address types in the registry. Outlook hands over messages that are addressed to an "allowed" address type to Exchange Server for further processing. When messages are addressed to an address type that is not included in the "allowed" list, Outlook does not reference Exchange Server but immediately returns an NDR message. This list in the registry is refreshed every time that Outlook starts a MAPI session in cached mode. This list is stored in the 01026687 registry entry under the following registry sub key: HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\<Outlook Profile>\13dbb0c8aa05101a9bb000aa002fc45a Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

"OPen the NDR and click the "Resend" button. Double-click the address in the "To:" header and see what the address type is. If the address is in a domain outside your organization the type should be SMTP." Tried this, the Email Type was set to MAIL TO. I assume we need to change this to SMTP? And what is this a property of, the auto-complete entry? If I change that value to SMTP, will that change that value for this entry going forward?

It was a recent bug that was due to Febs Outlook patches. Now I've seen this once in a while and it could be isolated issue, but if you have a number of users experiencing this then it could be related to the known issue. Hofix has been released below. You can also read about it in the long forum thread. Description of the Office Word 2007 hotfix package (wordconv-x-none.msp, word-x-none.msp): February 22, 2011 http://support.microsoft.com/kb/2475888/en-us?sd=rss&spid=11377 IMCEAMAILTO issue causing "Delivery has failed ...". http://social.technet.microsoft.com/Forums/en-US/exchangesvradmin/thread/56b2d50d-6855-444b-abed-89aaa9176a9fJames Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com