5.1.0 - Unknown address error 550-'5.1.1 <bla@bla.com>: user does not exist' - How to attach original email

[CraigFlorence33366]

Hello,

When we get a non-deliverable email we get the error message back , with a 35Kb attachment type subject.eml - but every email is the same size and when opened it has no contents. How do I attach the original, rejected, email to this error?

[Libin Varghese]

Was the NDR generated by the ESA and if so could you confirm what message tracking shows for that email?

The bounce emails generated by the ESA are as per bounce profile configuration under Network.

Regards,

Libin

[CraigFlorence33366]

I can't reply to you because of HTML formatting issues

[CraigFlorence33366]

I keep getting an error about HTML, then when it's removed I get an error about post spamming and having to wait 3600 seconds ...

[CraigFlorence33366]

Hi Libin,

I won't paste the full contents of the trace report immediately, I don't know how data protection works on here and it shows our email, plus a clients email and IP's - but here is an edited version of the error from the SMA trace:

29 Mar 2021 10:23:19 (GMT +01:00) (DCID 845) Message 883 to redacted@me.com delayed. Reason: 4.1.0 - Unknown address error ('451', ['4.2.0 Mailbox destination unavailable: redacted@me.com']) [('from', 'MTCG - My Company <us@mycompany.com>')]

Then that cycle repeats for a while, before finally ending with:

31 Mar 2021 00:29:13 (GMT +01:00) Start message 1114 on incoming connection (ICID 0).
31 Mar 2021 00:29:13 (GMT +01:00) A new message 1114 was generated to handle bounce of message 883.
31 Mar 2021 00:29:13 (GMT +01:00) Message 1114 enqueued on incoming connection (ICID 0) from .
31 Mar 2021 00:29:13 (GMT +01:00) Message 1114 on incoming connection (ICID 0) added recipient (us@mycompany.com).
31 Mar 2021 00:29:13 (GMT +01:00) Message 1114 (9029 bytes) from ready.
31 Mar 2021 00:29:13 (GMT +01:00) Message 1114 queued for delivery.
31 Mar 2021 00:29:13 (GMT +01:00) SMTP delivery connection (DCID 1086) opened from Cisco IronPort interface 2**.**.***.*** to IP address 1**.***.**.*** on port 25.
31 Mar 2021 00:29:13 (GMT +01:00) Delivery connection (DCID 1086) successfully accepted TLS protocol TLSv1.2 cipher ECDHE-RSA-AES256-GCM-SHA384 None.
31 Mar 2021 00:29:13 (GMT +01:00) (DCID 1086) Delivery started for message 1114 to us@mycompany.com.
31 Mar 2021 00:29:14 (GMT +01:00) (DCID 1086) Delivery details: Message 1114 sent to us@mycompany.com [(\'from\', \'"Mail Delivery System" <noreply@ces.cisco.com>\')]
31 Mar 2021 00:29:14 (GMT +01:00) Message 1114 Delivery Status: DELIVERED
31 Mar 2021 00:29:14 (GMT +01:00) Message 1114 to us@mycompany.com received remote SMTP response '2.6.0 <275dae$12q@esa2.hc1325-65.c3s2.iphmx.com> [InternalId=22780506541143, Hostname=LNXP265MB2457.GBRP265.PROD.OUTLOOK.COM] 18467 bytes in 0.085, 209.766 KB/sec Queued mail for delivery'.

On the ESA the bounce section is default, I think, as follows: Network > Bounce Profiles 

 

[svgeorgi]

I can see that the NDR was generated by a CES and it says that the recipient's mailbox wasn't available:

'451', ['4.2.0 Mailbox destination unavailable: redacted@me.com']) [('from', 'MTCG - My Company <us@mycompany.com>')]

Have you checked with the recipient if that's a valid email address, or if the recipient's server will accept such email?

I do believe that the recipient's address really doesn't exist as the remote server is saying back to your ESA when it tries to deliver it.