XG MTA 550 No Such User or 550 Relay Not Permitted

All,

  I'm having an issue. XG Firewall 16.05.6 MR-6 in MTA mode. Exchange 2016 using the XG as a smarthost.

I'm having users report that if they send an email to multiple recipients (known correct and valid email addresses) that they often bounce with 550 no such user or relay not permitted for one random recipient.

The error message in full with the obvious exclusions...

Sophos Firewall was unable to send the following mail:
----------------------
From: user@sourcedomain.com
MessageID: <8ac080d6c432407a9fa4aedd0fb9302b@sourcedomain.com>
Sent on: 2017-09-13 15:12:26

Mail delivery to following recipients failed:

user@destinationdomain.com - 550 relay not permitted

Or...

Sophos Firewall was unable to send the following mail:
----------------------
From: user@sourcedomain.com
MessageID: <63e921cb810848b99dd2d12dbb1efbc0@sourcedomain.com>
Sent on: 2017-09-10 11:04:41

Mail delivery to following recipients failed:

user@destinationdomain.com - 550 relay not permitted

They can then email to each recipient individually with no bounce. When done so, email delivery has been confirmed at the other end. Has anyone run into this?

Thanks

Gary

  • Gary,

    read the log from the advanced shell. cat /log/awarrenmta.log | grep "user@domain.local"

    You should find more information on that.

    Also check the number of maximum users the email can send to on XG MTA.

    Regards

  • In reply to lferrara:

    Maximum recipients is set to 100. These issue occur with only 3 or 4 recipients. I'm seeing emails in the awarrenmta log. From and to etc with time stamps. There's no detail however. Is this confirming that the message was in fact delivered?

    I also found something else interesting. I have two WAN IPs. All of these issues only seem to occur when using one of my two providers. I've used MXtoolbox and everything looks just fine on both connections. I also spoke with the ISP, nothing is being blocked.

    I'm using the SecurityAppliance_SSL_CA on the MTA as well. Issue?

    I'm left very confused.

    Gary