topic Re: Messages bouncing back undelivered in Email

Messages bouncing back undelivered

PeterW5 — Mon, 24 Mar 2025 15:29:40 GMT

Just attempted a small distribution of a message and 4 have bounced back as undelivered. The reason quoted is that they are "Unauthenticated email from talktalk.net is not accepted due to domain's DMARC policy. Please contact the administrator of talktalk.net domain if this was a legitimate mail."

Please can someone identify how I can contact the "administrator" to try and resolve this. To the best of my knowledge there was no other reason for these messages to be unusual.

Thanks

Re: Messages bouncing back undelivered

Ady-TalkTalk — Tue, 25 Mar 2025 09:43:01 GMT

Hi PeterW5, send the mail from webmail direct to the recipients without forwarding and it'll get through.

Ady

Re: Messages bouncing back undelivered

PeterW5 — Tue, 25 Mar 2025 09:52:48 GMT

Apologies, I should have been more specific in what I was trying to do. I was using a distribution list set up in Outlook (old version in MS Office) and so I was not actually trying to forward anything but rather send each of the recipients a message directly. To do the same from webmail would require too many individual messages.

Re: Messages bouncing back undelivered

Ady-TalkTalk — Tue, 25 Mar 2025 10:39:29 GMT

What settings are you using in Outlook? The DMARK message is due to mail forwarding.

Ady

Re: Messages bouncing back undelivered

PeterW5 — Wed, 26 Mar 2025 07:40:18 GMT

Thanks Ady. Unfortunately I am not sure what sort of settings you refer to. I am sending a message from @talktalk.net to a small distribution list which has been previously prepared in my contacts. It is exactly the same message to each intended recipient and so I do not see any link to the idea of 'forwarding'. certainly this approach has never been a problem before the recent past. Interestingly when I try to forward any SPAM messages to the GCHQ site and TalkTalk they do not work for GCHQ (presumably because it has been forwarded but the message does get through to TalkTalk. What do we have to do to get recipients to see our TalkTalk messages as friends?

Re: Messages bouncing back undelivered

Ady-TalkTalk — Wed, 26 Mar 2025 07:42:12 GMT

Hi PeterW5, the email settings you should be using are found in the Email Settings help article.

Ady

Re: Messages bouncing back undelivered

PeterW5 — Wed, 26 Mar 2025 09:21:46 GMT

Thanks Ady. I have checked the settings in Outlook and they are all correct so that does not seem to be part of the problem. Also know that some messages work and only some are rejected by the recipient's system.

Re: Messages bouncing back undelivered

Paddypegg — Wed, 26 Mar 2025 10:16:40 GMT

I have had exactly the same problem this morning - the messages that have been returned were all to BT email addresses. Similar problem a couple of months ago. I was told then in chat that there had been a problem between BT & Talktalk but engineers were working on it and it has been OK until today. Also it seems my emails are going into recipients spam boxes. How do I contact Postmaster ? Thanks

Re: Messages bouncing back undelivered

Ady-TalkTalk — Wed, 26 Mar 2025 13:19:23 GMT

Thanks PeterW5, if you send directly to 1 of the addresses that don't go through from webmail does it go through?

Ady

Re: Messages bouncing back undelivered

PeterW5 — Wed, 26 Mar 2025 14:59:21 GMT

Ady I have tried sending off four messages individually that have previously bounced back. So far two of them have bounced straight back (can sometimes takes a while). One said that the error was 554 5.7.9 Message not accepted for policy reasons and then a link which said :

A 553 or 554 SMTP error indicates an email could not be delivered due to a permanent problem. Message delivery can be permanently deferred because:
- You're trying to send a message to an invalid email address.
- Your message failed authentication checks against your sending domain's DMARC or DKIM policy.
- The message contains characteristics that Yahoo won't accept for policy reasons.
- Other suspicious behavior which leads Yahoo to issue a permanent rejection for your SMTP connection.
- Your IP is listed by Spamhaus. Please check with https://www.spamhaus.org.
If you consistently receive 5xx errors when sending to Yahoo, we encourage you to review our Sender Requirements & Recommendations, since 5xx errors can be a symptom of a more widespread, general problem.
You should not retry sending an email that comes back with with a 5xx error. List managers should have a policy for removing email addresses that generate 5xx errors/bounces.

The other came back with a message error code 550 5.7.1 Message rejected per senders DMARC policy. My understanding is that the DMARC aspect is something which relates to the ISP rather than anything I might do in Outlook.

Re: Messages bouncing back undelivered

nickprince — Wed, 03 Sep 2025 15:10:15 GMT

Same problem here:

<s*****************@hotmail.co.uk>: host
    eur.olc.protection.outlook.com[52.101.73.23] said: 550 5.7.515 Access
    denied, sending domain TALKTALK.NET doesn't meet the required
    authentication level. The sender's domain in the 5322.From address doesn't
    meet the authentication requirements defined for the sender. To learn how
    to fix this see: https://go.microsoft.com/fwlink/p/?linkid=2319303 Spf=
    Pass , Dkim= Fail , DMARC= Pass [PH8PR05MB9268.namprd05.prod.outlook.com
    2025-09-03T14:44:05.342Z 08DDE95809CAA86C]
    [AM0PR03CA0088.eurprd03.prod.outlook.com 2025-09-03T14:44:04.206Z
    08DDEA9124FA4B20] [AMS0EPF00000191.eurprd05.prod.outlook.com
    2025-09-03T14:44:05.419Z 08DDE263C5F6367F] (in reply to end of DATA
    command)

Re: Messages bouncing back undelivered

siphosethu-TT — Wed, 03 Sep 2025 15:57:59 GMT

Hi there @nickprince, please start your own thread so we're able to assist you. Thanks