Thanks, Mark, you are saving my life here.
It's working now due to permission issued because I used root account to create mailing list in bash command.
by the way, my mailman3 installed on Debian 13 OS via Debian package. I didn't create mailman user. Now, it is running under list:list root@lacll-mailman:/var/lib/mailman3/queue/shunt# ps aux | grep mailman avahi 833 0.0 0.0 6248 4180 ? Ss 11:44 0:00 avahi-daemon: running [lacll-mailman.local] list 6408 0.0 0.6 107900 98648 ? Ss 13:04 0:01 mailman: master postgres 6422 0.0 0.1 220648 18936 ? Ss 13:04 0:00 postgres: 17/main: mailman3 mailman3 ::1(41028) idle list 6423 0.0 0.6 110916 102300 ? S 13:04 0:01 mailman: runner [archive] list 6424 0.0 0.6 110680 102120 ? S 13:04 0:01 mailman: runner [bounces] list 6425 0.0 0.6 107924 99380 ? S 13:04 0:01 mailman: runner [command] list 6426 0.0 0.6 111980 102572 ? S 13:04 0:01 mailman: runner [in] list 6427 0.0 0.6 183724 102648 ? Sl 13:04 0:01 mailman: runner [lmtp] list 6428 0.0 0.6 112052 103040 ? S 13:04 0:01 mailman: runner [out] list 6429 0.0 0.6 111928 103396 ? S 13:04 0:01 mailman: runner [pipeline] list 6430 0.0 0.6 118076 107588 ? S 13:04 0:01 gunicorn: master [mailman: runner [rest]] list 6431 0.0 0.6 107856 98940 ? S 13:04 0:01 mailman: runner [retry] list 6432 0.0 0.6 110560 102108 ? S 13:04 0:01 mailman: runner [task] list 6433 0.0 0.6 110824 102244 ? S 13:04 0:01 mailman: runner [virgin] list 6434 0.0 0.6 111980 102776 ? S 13:04 0:01 mailman: runner [digest]
If I would like to change to other user, where should I change it. Greatly appreciate if you can guide me on this as well.
Thanks, Marin