Messages bouncing back undelivered

[PeterW5]

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

[PeterW5]

Thanks Ady. Unfortunately I am not sure what sort of settings you refer to. I am sending a message from bishopwearmouth@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?

[Ady-TalkTalk]

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

Ady

[PeterW5]

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. 

[Ady-TalkTalk]

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

Ady