If you run a mailing list, you probably need to look into ARC:

> Authenticated Received Chain (ARC) is an email authentication system designed to allow an intermediate mail server like a mailing list or forwarding service to sign an email's original authentication results. This allows a receiving service to validate an email when the email's SPF and DKIM records are rendered invalid by an intermediate server's processing.[1]

* https://en.wikipedia.org/wiki/Authenticated_Received_Chain