virginmedia SMC Policy Violation bounce error

[CWildeRE]

Hi,

We're an ESP sending emails on behalf of cleints who are receiving the following bounce error from virgin media domains (blueyonder, ntlworld, virginmedia) across multiple different domains and IPs:

SMTP service unavailable: "421 4.2.0 MXIN618 Temporary SMC Policy Violation detected, retry later ;id=KdKFlqEMxa7TsKdKFlL2Ap;sid=KdKFlqEMxa7Ts;mta=mx12.tb;dt=2021-03-12T09:39:16+01:00;ipsrc=xx.xx.xx.xx;" received from mx.tb.ukmail.iss.as9143.net (212.54.56.11) while connected from SENDINGDOMAIN.co.uk (xx.xx.xx.xx) to mx.tb.ukmail.iss.as9143.net (212.54.56.11)

 We have tried "sending later", as suggested in the error but no emails are being allowed through. Would someone please be able to help me with the cause of this error, and how we may resolve it moving forwards? I can't find any information on it online nor action I can take for it to be removed.

If there is elsewhere better to post this question, please let me know and I'll be happy to move it.

Many thanks,

Chris

[CWildeRE]

Great find, at least I know what the potential cause is now. I'll leave it to the VM Mod Team to escalate rather than going direct to ziggo

[Hayley_S]

Hello 

Thank you for posting on our community page 🙂

Sorry for the confusion with this error.

Please can you send me a a Private Message with the unredacted version of the error code? Also the email headers?

Thanks, 

[HowardML]

@CWildeRE  - please send the details by private message. Click on Hayley's name in red and follow through. 

@Hayley_S 

Hayley - please be careful. You must ask for this kind of information by private message and make that explicit in your reply. All too often people reply on the Forum and that breaches privacy.  You may only get a sample header if the ESP cannot match an error message with the email that generated it. Fingers crossed they can.

[CWildeRE]

Sent via private message (I think, the window wouldn't disappear when I clicked send message so you might have got a few!).

I don't have access to the email headers unfortunately.

[HowardML]

Just to add. The email headers will add nothing to the information needed to resolve this. The unredacted error message is important because it shows the IP address of the sending server which is being greylisted. As you can see from the link I posted all that was necessary to get that case resolved by Ziggo who run the servers was that IP address.

@CWildeRE  - it strikes me that I should have asked you to run a scan using MX Toolbox or similar on the server IP address used for sending to check its reputation. I had a ghastly case last week where the server was clean on one scan site but came up with a UCE listing on MX toolbox. Caused immense confusion.

[CWildeRE]

I've carried out quite a few rDNS, IP and DNSBL blacklist checks already (Including MX Toolbox) - had a few minor listings that I've had removed but nothing major. Given the scope of clients that this error's occurring on it seems too widespread to be a blacklist issue from my view.

[HowardML]

That's fine. Your sending IP is clean as far as you know. I would have expected any decent ESP to have done those checks, but I felt obliged to ask to rule out the possibility. One of my fellow VIPs might even have asked you for your IP address on the basis of assurances about confidentiality which I could also give. But I didn't want to go that far. We've only just met!

The rDNS check is great. That rules out a misconfigured server being the cause of this. The rDNS must match the server forward DNS lookup (I hope I have got this right, I told you I was an amateur).

The other checks we often look at is whether the SPF record , DKIM and DMARC entries for the server are correct? 

VM need to get the views of Ziggo as to why greylisting seems to be happening.

[CWildeRE]

@Hayley_S did you receive the private message OK?

[Hayley_S]

Hello @CWildeRE

I am sorry but I can not see a PM from you 😞

Please can you try and message me again?

Thanks,

[CWildeRE]

Hi Hayley,

I received a private message from you, but it disappeared and I cannot reply to it. Please could you provide an email address I can send the details to, or message me again?