[Mailman-Users] Moderation requests flood after migrating from MM2 to MM3 on Debian

Dear all,

this may be of course related to Debian version of Mailman3 (currently 3.3.3, Debian 11 Bullseye), but I hope someone may point me towards a direction in which i should start digging in order to resolve this issue.

I have recently migrated two lists from perfectly working MM2 to MM3 using the migration approach outlines in the documentation (https://docs.mailman3.org/en/latest/migration.html), i.e.

a) mailman create foo-list@example.com b) mailman import21 foo-list@example.com /path/to/mailman2/foo-list/config.pck c) python manage.py hyperkitty_import -l foo-list@example.com $var_prefix/archives/private/foo-list.mbox/foo-list.mbox d) python manage.py update_index_one_list foo-list@example.com

I do not have the hyperkitty working properly, but that is not important as for now. What is however important, is that for both lists mailman3 generates approximately every minute a message that it tries to send to the list and the message is catched by the mailman and requires moderation. As a result, I have some 1000 moderation requests for each of the list every day. The requests are mostly of the type

Sender: foo-list-owner@example.com
Subject: foo-list@example.com_post_from_foo-list-owner@example.com_requires_approval
Reason: The message is not from a list member

I can see also some weird handling of bounced messages (if we try to send an e-mail that bounces, in my opinion it should be silently discarded or sent to foo-list-owner@example.com).

Sender: microsoftexchange329e71ec88ae4615bbc36ab6ce41109e@exampledomain.onmicrosoft.com
Subject: Undeliverable:_[FOO]_Meeting
Reason: The message is not from a list member

I have a strong feeling that I misconfigured MM3 somewhere or that I did not do my homework properly and failed to read relevant parts of the documentation. Any ideas where to start?

Thanks a lot!

Jan