user doesn't exist on mail server

Posted on 2007-08-08
Medium Priority
Last Modified: 2008-01-09
We are having a problem with a couple of sites that we send email frequently to. Some of the users at their end are getting messages back saying that the user doesn't exist at our end, yet, my users have sent and received email from the same users their end.

We are running Exchange 2003 on a Windows 2003 Small Business Server. We are also running the GFI Mail Essentials spam software on the server.

Is this a problem at our end? Is there something I can check at my end? I can send these users (at our end) email without any problems (from an external email address)
Question by:johnbowden
  • 2

Accepted Solution

december41991 earned 390 total points
ID: 19654458
Is the NDR 5.1.1 ? can you be please more specific about the exchange environment. How many Exchange server ? are the user in the same exchange ?
LVL 104

Assisted Solution

Sembee earned 360 total points
ID: 19655328
How do you receive email?
Directly or via your ISPs Server?


Author Comment

ID: 19689528
I don't have an NDR report since the problem happens at their end. I don't know what mail they are running either. I can find out.
This is what I have is this
"The e-mail account does not exist at the organization this message was sent to.  Check the e-mail address, or contact the recipient directly to find out the correct address."

Mail is don't via SMTP. Our internet connection is a high speed DSL connection with a static IP.


Author Comment

ID: 19848121
Lately, the mail has been flowing properly but as far as I'm concerned, nothing was done. Something at either end was refusing email even though it was valid. I have another customer now that this is happening to but in this case, it's two bigger ISP's that the messages are being returned so now I'm not so sure that it was something that I can resolve.

The error messages are similar to these two listed below;
   Delivery to the following recipients failed <email address>
   550 unknown user <email address>

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