Some list members are experiencing a high levels of bounced messages or unsubscriptions
If some of your list Yahoo or AOL mailing list members are experiencing a high levels of bounced messages followed by automatic unsubscriptions, it might be due to policy called DMARC Yahoo and AOL implemented in the spring of 2014, and Gmail afterwards.
We have setup a new Mailman Mailing List server with Mailman 12.8., which offers new settings for domains whose D-Mark policy is set to Reject or quarantine.
See the Recommended Mailing List settings to mitigate D-MARK policy.