On Wed, 4 Dec 2019 at 17:54, Constantine A. Murenin <mureninc@gmail.com> wrote:

> Again, these are not a user messages or regular list traffic, they're admin/moderator messages addressed to an admin of a list.

So, to clarify the OP issues here — you're using Gmail on your domain
(aka G Suite), and are also a Mailman administrator (on same or
different domain?), and are unable to properly use Mailmain, because
Gmail?

No. I'm a mailman administrator on some domain completely unrelated to google in any way, and google is rejecting admin email from said mailman instance to (so far) one list admin who has a gmail.com address.