[Mailman-Users] Importing from 2.1.12-18.el6 to 2.1.15-17.el7

[Dean Collins]

This is Mailman 2.1.15-17, qmail, CentOS 7.

I've got a new server and set up a test list, say, mylist at mydomain.com.

Subscribers include me at mydomain.com (the same domain the list is on) and
various addresses from other domains/servers (a couple of servers I run,
plus Gmail and AT&T.)

Mail sent to mylist at mydomain.com from any subscriber gets archived -- and
distributed to me at mydomain.com. But none of the other subscribers receive
the list mail.

Non-list, regular mail works fine. Using me at mydomain.com I can send to
anyone (and they receive it) and receive from anyone.

I know less about mail than just about anything else in the world, so any
suggestions as to what might be wrong would be appreciated. Thanks!

Dean