Hi friends.
I'm now getting a 500 server error upon signing up a new username on the web-based front end. The username is created in the back end, but the verification email does not get sent.
This is GNU Mailman 3.3.9 (Tom Sawyer), venv, Ubuntu 24.04LTS, PostgreSQL, Postfix
Here are the corresponding logfile entries from mailmanweb.log: smtplib.SMTPRecipientsRefused: {'redacted@gmail.com': (504, b'5.5.2 <mail>: Helo command rejected: need fully-qualified hostname')}
and from mail.log: Oct 14 12:06:26 domain postfix/smtpd[722764]: NOQUEUE: reject: RCPT from localhost[127.0.0.1]: 504 5.5.2 <mail>: Helo command rejected: need fully-qualified hostname; from=<root@lists.domain.tld> to=<root@localhost> proto=ESMTP helo=<mail>
lists.domain.tld is the domain for Mailman3. I don't know why it's trying to send email from root@.
I've seen places where 'localhost' appears in the Mailman settings (settings.py, mailman.cfg, mailman-web.py), and tried changing them to the host's FQDN and restarting mailman3 and mailman3-web, but the problem persists.
Suggestions will be appreciated. ~ Greg