#5.5.0 smtp;550 Recipient address rejected: User unknown in relay recipient table

Posted on 2006-11-02
Last Modified: 2008-01-09
This message appers once a while about specific users.ANy ideas??
Question by:ykamp
LVL 10

Expert Comment

ID: 17860736

The delivery lookup is on the receiving side.  So the most likely cause is an error there; or maybe the account has been closed.  The only thing you need to check on the sending side is that the address is correct.


Expert Comment

ID: 17862524
Yes if it is indeed about specific e-mail accounts then those accounts no longer exist or more specifically the domain no longer exists.  I would check to make sure that the recepient's domain has a valid MX record.  If the domain doesn't then the SMTP server will kick this error back to you telling you that it is not able to relay the mail message to that user's domain or it is too many hops.  I've had this happen when too many forwards in a person's e-mail is detected and the e-mail is lost in transit.

If you need help locating the MX record reply to this post with just the portion of the specific accounts or a sample of them and I'll help you out.

Expert Comment

ID: 17864951
Check this list for the NDR messages for Exchange.

Although this seems to be a Postfix SMTP server looking at the error message.

According to some PostFix help file:
Valid recipient addresses are listed with the relay_recipient_maps parameter. The Postfix SMTP server rejects invalid recipients with "User unknown in relay recipient table". AKA the user doesn't appear to exist on the other side.

Author Comment

ID: 17883344
Underlying SMTP 500 error.  Our server tried ehlo, the recipient's server did not understand and returned a 550 or 500 error.  Set up SMTP logging.???


Accepted Solution

Shankadude earned 500 total points
ID: 17891712
Your mailserver tried to make a connection to a mailserver to deliver its mail. This connection setup is started by sending a command ('ehlo') to the destination mailserver.
If the mailserver is listening to commands it will answer with a code like 200 Ok, or 550 <error>.
If you want to know what exactly is causing the error you can configure your mail system so that it generates logging.

For Exchange you can do this by entering the Exchange System Manager, go to your outgoing mailserver, open the properties and go to the diagnostics tab (Don't know for sure if it's there, got no Exchange here at the moment).

If you're using some other system like PostFix or QMail look at their respective manuals for the logging. Most of the time this loggin will be in /var/log/qmail or something like that on Linux/Unix.

Perhaps we all started on the wrong foot. What system gives this error message ? How are the clients mailing?

Featured Post

VMware Disaster Recovery and Data Protection

In this expert guide, you’ll learn about the components of a Modern Data Center. You will use cases for the value-added capabilities of Veeam®, including combining backup and replication for VMware disaster recovery and using replication for data center migration.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Many people tend to confuse the function of a virus with the one of adware, this misunderstanding of the basic of what each software is and how it operates causes users and organizations to take the wrong security measures that would protect them ag…
I don't know if many of you have made the great mistake of using the Cisco Thin Client model with the management software VXC. If you have then you are probably more then familiar with the incredibly clunky interface, the numerous work arounds, and …
This is used to tweak the memory usage for your computer, it is used for servers more so than workstations but just be careful editing registry settings as it may cause irreversible results. I hold no responsibility for anything you do to the regist…
Hi friends,  in this video  I'll show you how new windows 10 user can learn the using of windows 10. Thank you.

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question