Gmail no accepting emails

[Chocolate2]

Gmail have now on two occasions not accepted emails I have sent to two separate email accounts.  I keep getting the following message:-

(reason: 550-5.7.26 Unauthenticated email from talktalk.net is not accepted due to)

   ----- Transcript of session follows -----

... while talking to gmail-smtp-in.l.google.com.:

>>> DATA

<<< 550-5.7.26 Unauthenticated email from talktalk.net is not accepted due to

<<< 550-5.7.26 domain's DMARC policy. Please contact the administrator of

<<< 550-5.7.26 talktalk.net domain if this was a legitimate mail. To learn about

Both contacts have confirmed the email has not been received, and has not been placed in spam.

Apparently the domain needs a DKIM how do I get this?

[Ady-TalkTalk]

Hi Chocolate2, please make sure you're using the settings you'll find in the Email Settings help article. 

Ady

[Billx]

Thanks, @mbsharp 

Bill

[mbsharp]

The settings are in the outgoing server. Strictly none are compulsory but in practice SPF is an absolute minimum and I think Gmail requires that DMARC is present. DKIM provides for encryption keys so is the top level. The receiver will have its own stepwise rules for deciding whether a message passes and what to do if it doesn't. You may be able to see the rule processing stages if you examine the full message source but that requires you to have received it.

[Billx]

Are these settings in the TalkTalk outgoing server or in Gmail's incoming server?

Are these 3 settings required from TalkTalk by Gmail

When I receive an email from Gmail into TalkTalk, I can see the following:

SPF: Pass with domain gmail.com
DKIM: None
DMARC: Pass

So you can see that it passes, even though there is no DKIM setting.

When I receive an email from TalkTalk into Gmail, I can not see any of these 3 settings, but it still is received at Gmail.

So, if these 2 settings are at TalkTalk,  does it help TalkTalk  to avoid phishing, or does it help Gmail to avoid phishing?

Bill

[mbsharp]

SPF, DMARC and DKIM are settings placed in the email server which together authenticate the server as the true originator of the message. As such they are not personal to you and you cannot obtain any of them for yourself. Unfortunately, authenticating the server is not enough in this day and age as the message content itself can be dangerous/spam. That leads to reputation services such as spamcop which set scores based on content and end user opinions/rejections. Those services are entirely automated and a block, once set, will remain in place until any stream of rejections has ceased.