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Ex2007 User to User unknown user error 550

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Ex2007 User to User unknown user error 550 - 3.Jul.2008 11:51:36 AM

acdii

Posts: 9
Joined: 25.Mar.2008
Status: offline

I have one user on Exchange 2007 standalone server that when they try to send an email to another user, they get a 550 rejection.
Your message did not reach some or all of the intended recipients.
      Subject: test
      Sent:     7/3/2008 10:25 AM
The following recipient(s) cannot be reached:
      user name on 7/3/2008 10:25 AM
            550 unknown user <user@domain.org>

The same user can send emails to all other users on the server and can recieve email from the user he gets the 550 from. The message isnt very helpful, nothing else to go on. The user who comes up as unknown is getting email from all other users and from external accounts.

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RE: Ex2007 User to User unknown user error 550 - 3.Jul.2008 11:57:50 AM

uemurad

Posts: 5146
Joined: 7.Jan.2004
From: California, USA
Status: offline

Does it do the same thing if a reply is sent to a message from that same address? The most common cause for this is a cached address. When your user starts to type in the address, does it attempt to autofill? If so, highlight the autofill entry and press Delete, then complete the address and send.

_____________________________

Regards,

Dean T. Uemura
Microsoft MVP - Exchange
exchangeguy.blogspot.com
uemurad@yahoo.com

(in reply to acdii)

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RE: Ex2007 User to User unknown user error 550 - 3.Jul.2008 12:00:23 PM

acdii

Posts: 9
Joined: 25.Mar.2008
Status: offline

I was thinking the same thing and waiting on the customer to cal back to check that part out. The bounce though shows the email address as being correct.

(in reply to uemurad)

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RE: Ex2007 User to User unknown user error 550 - 3.Jul.2008 12:08:33 PM

uemurad

Posts: 5146
Joined: 7.Jan.2004
From: California, USA
Status: offline

I've seen that happen. You can also check Message Tracking to see what the server is doing with the outbound message, you can check the SMTP log, and you can perform a manual test with Telnet.

_____________________________

Regards,

Dean T. Uemura
Microsoft MVP - Exchange
exchangeguy.blogspot.com
uemurad@yahoo.com

(in reply to acdii)

Post #: 4