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exchange 2003 outlook

Posted on 2009-05-01
Medium Priority
Last Modified: 2013-11-22
i have an exchange 2003 server and the clients use outlook 2003. i just want to confirm the error i'm having. the error on the client states

"there was a smtp communication problem with recipient's email server #5.5.0 smtp; 550 recipient address rejected: user unknown"

i assume this problem is just as it states, the address is bad, so for instance if the client sent to abc@mail.com, as the message states, there isn't an abc@mail.com. so maybe the client typed the name incorrectly, or there isn't an abc@mail.com, or there was an abc@mail.com but it has change, or was removed. are these assumptions correct?
Question by:JeffBeall
LVL 38

Accepted Solution

Hypercat (Deb) earned 2000 total points
ID: 24281060
The 5.5.0 error is pretty generic. However, in the case of what you have posted above, I would accept the added reason for rejection and assume that the recipient's email address was invalid for whatever reason. As you said, it could have never existed, it could have been removed for some reason, or it could have been changed; or the sender could have simply mis-typed the address.  In these cases, I usually advise the sender (your user) to contact the recipient and ask him/her to send an email to your user, and then they can reply to that email, ensuring that they have the correct address.  If the reply email still doesn't go through, then the NDR is giving you invalid information and there is some other communication issue between your server and the recipient's email server.

Author Closing Comment

ID: 31576961
Thanks for the help. I think I'll try to have the client contact the person in question and do like you said and have them send an email.

Expert Comment

ID: 24281198
Hi JeffBeall,
Delivery notification error 5.xx is a permanent delivery failure
Possible issues.
1.      Remote computer may reject your domain.
2.      May be issue with the recipient SMTP relay server.
3.      Due to recipient unavailable.
You can find same information with the help of message header.
For more information about the Delivery status notification errors visit the following link


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