Hi David, thank you for this info. It is indeed a help. I have previously received very contradictory information on this subject from other sources. I have already configured Mailman correctly according to the instructions you recommended, but I was not aware of the option to remove the DKIM header. If the DKIM header can be removed, I think that the prefix [Cin] and the footer can be reactivated, because the original DKIM is removed. So my understanding is, if I'm wrong, please let me know. We are trying this option and I will follow the next days how Mailman behaves. Thanks again for the tip. @IgorBeg Since I found a way to solve the problem with DKIM, I have activated the prefix and footer. We will see how Mailman and Gmail will behave with these settings. Sam Am 10.07.20 um 15:09 schrieb David Given:
Trying to preserve the original DKIM signature is unlikely to work --- Mailman tends to regenerates the headers and body from parsed copies so the details of the formatting can change, which breaks the signature. The only thing which actually works here is to strip the DKIM signature (preferably after checking it) and resigning the message when Mailman sends it. See for example https://doc.coker.com.au/internet/dkim-and-mailing-lists/.