Bounce by Destination Server

[Ah15]

When we try to send an email to the specific user we get this message "5.1.0 - Unknown address error 550-'5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup"

But the recipient able to receive the message in another test, and then return back to the old status of not receiving and the bounce message returns to the sender.

Kindly advice.

[Mathew Huynh · Accepted solution]

Hey Ah15,

Personally I don't think is your ESAs problem.

5.1.0 - Unknown address error 550-'5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup

This bounce code means ESA received 550-5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup by the destination server when attempting to deliver.

The fact that it's inconsistent could be one of two things.

1) You're sending to different mail servers where one mail server is rejecting at a recipient lookup and the other isn't doing this check

2) the recipient server is having intermittent recipient validation functionality.

This response RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup means that they did a lookup (looks like a MS response to be honest) and it found no such mail box.

Thanks,

Mathew

[Ah15]

Thanks Mathew for your reply.

Also the following error related to the same problem, I got an error message that the destination server rejects the connection with the below message.

Remote Server returned '554 5.0.0 <[41.33.88.5] #5.0.0 smtp; 5.1.0 - Unknown address error 510-'Error: invalid sender domain or DNS temp failure' (delivery attempts: 0)>'

It is not considered as a problem on CES also, alright?

[Mathew Huynh · Accepted solution]

Hey Ah15,

This one could be a bit more tricky - did you get this in an NDR generated by your CES?

Or was it an NDR where you see it was generated by a different server?

Depending on which hop we can determine; going off my assumption:

Remote Server returned '554 5.0.0 <[41.33.88.5] #5.0.0 smtp; 5.1.0 - Unknown address error 510-'Error: invalid sender domain or DNS temp failure' (delivery attempts: 0)>'

510-'Error: invalid sender domain or DNS temp failure' (delivery attempts: 0) is the original bounce reason, they could resolve the sender address. The They is up for speculation at this point.

5.1.0 - Unknown address error this looks like it could have inputted by the CES: best way to find out is try to find this email inside your message tracking, if it comes in as a fresh new email - then it's an NDR generated by another server, if the CES generated this NDR then you would see it in the DCID portion of the original email.

5.0.0 <[41.33.88.5] #5.0.0 smtp This is definitely not a CES response, but the IP is interesting; that looks potentially to be the IP that attempted the delivery?

554 is a generic rejection.

Regards,

Mathew

[Ah15]

Hello Mathew,

The message details shows that CES generate this NDR, 
Below is the log detail: (DCID xxx) Message xxxx to (Recipient) bounced by destination server. Reason: 5.1.0 - Unknown address error ('510', ['Error: invalid sender domain or DNS temp failure']) [('from', 'Sender'), ('to', '"Recipient')]

[Mathew Huynh · Accepted solution]

Hey Ah15,

If that was found within the message tracking at the DCID level; then i would venture to advise you to check the email sender domain per the message.

I assume this is an outbound email as you are sending out to the internet and they rejected it with 510', ['Error: invalid sender domain or DNS temp failure']) [('from', 'Sender'), ('to', '"Recipient')]

If it is outbound; definitely check the sender domain; if it is your own domain.

Make sure your domain has valid A record available and corresponding PTR record.

Make sure the MX record resolves properly as well.

If your envelope sender domain is all resolvable; check the email for the "From" header and also if there is a "Sender" header; if so do the same checks against the domains here.

If all checks out - you definitely need to contact the administrator of recipient domain to find out why is it rejecting your sender address(es).

Thank you,

Mathew

[Ah15]

Thanks Mathew for the clarification. Appreciated.