Stephen J. Turnbull wrote:
This is almost certainly due to a recent policy change at Gmail, where they are requiring "from alignment"[1] but only for Gmail authors. That is, Gmail does not publish a p=reject policy, but the effect on Gmail recipients (only) is the same as if they did -- they all bounce every time a Gmail user posts.
Another way to prevent gmail users from having delivery disabled and
being unsubscribed because of this is to enable VERP probes (set
verp_probes: yes in the [mta] section of mailman.cfg). Since the
probes are not sent from a gmail user, they won't bounce and the user's
delivery won't be disabled.
This is not a fix for the issue as the gmail users will still not receive posts from other gmail users, but they will receive other posts and won't get their delivery disabled by bounce.
-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan