Chihurumnaya Ibiam via Mailman-users writes:
I've removed this [Dovecot?],
You mean you uninstalled it? If not, where did you remove it from?
and it does seem like dovecot still runs when mailman hands mail to lmtp,
I assume by "seem like dovecot still runs" you're referring to the log entry below. If not, what evidence are you seeing that dovecot is running?
but I don't see any authentication issues, the logs show this;
lists postfix/lmtp[1376243]: 458381A894B: to=<mailman@lists.sugarlabs.org>, orig_to=<mailman>, relay=localhost[127.0.0.1]:24, delay=0.03,
This says the postfix is sending to 127.0.0.1 over port 24. This is probably Mailman, since LMTP is the only way for Postfix to send mail to Mailman, and Mailman is trying to process mail according to your logs.
delays=0.02/0/0.01/0, dsn=5.1.1, status=bounced (host localhost[127.0.0.1] said: 550 5.1.1 <mailman@lists.sugarlabs.org> User doesn't exist:
This means that whatever is listening on port 24 doesn't know about the 'mailman' user. Mailman only knows about lists in the postfix_lmtp file (that is compiled to postfix_lmtp.db).
mailman@lists.sugarlabs.org (in reply to RCPT TO command))
The user does exist, which is the weird part.
Not really. Postfix knows how to deliver to local users in file-based mailboxes, but it's delivering via LMTP or SMTP to port 24. I suppose Dovecot does as well, but if it's been uninstalled by a package manager, the running instance will have been stopped and there won't be anything to run. Most likely the listener on 24 is Mailman, which does *not* know how to deliver to local users at all.
I'm starting mailman via systemd, and the mailman config was passed through an environment variable - MAILMAN_CONFIG_FILE -.
You should run "mailman -C /etc/mailman3/mailman.cfg conf -s mta", which will tell you the basic information about Mailman's handling of external mail both incoming and outgoing.
The installation instructions <https://docs.mailman3.org/en/latest/install/install.html> don't say anything about mailman listening on a port
That's implied by using LMTP which is a network protocol. Mailman 3 defaults to using 8024 for that port. If you're using Postfix, that port will be in the postfix_lmtp file, so it's configured automatically. I forget how other MTAs get information about the Mailman host and port.
Which installation method did you use? Your package manager, or virtualenv? If it's a package manager, who knows what it has configured.
I've removed authentication and the only error in the log is the one I shared above, although there are some errors in mailman smtp logs;
1551 Jan 31 12:44:03 2026 (4128778) <176979064563.3611678.6370323034981829398@lists> smtp to sugar-devel@lists.sugarlabs.org for 1 recips, completed in 0.009501457214355469 seconds
This seems to be the incoming message to Mailman, which Mailman accepted. The Message-ID (in <> angle brackets) is not of the recommended form. It should have the full domain (presumably lists.sugarlabs.org) to ensure global uniqueness.
1552 Jan 31 12:44:03 2026 (4128778) <176979064563.3611678.6370323034981829398@lists> post to sugar-devel@lists.sugarlabs.org from sugar-devel-confirm+edc5e1df6d76fe7955475023efd08101ed2edb17@lists.sugarlabs.org, 1707 bytes, 1 failures
I'm not sure what's going on here, but I think there's a serious configuration problem because Mailman is sending confirmation codes (probably for subscriptions) back to the list.
What is your postfix setting for recipient_delimiter? That needs to be '+' or possibly '+-'. If it's '-', that will cause this kind of mail loop, I think.
1553 Jan 31 12:44:03 2026 (4128778) <176979064563.3611678.6370323034981829398@lists> delivery to sarthakkad2005@gmail.com failed with code 444, SMTP AUTH extension not supported by server.
The above 2 say that you're trying to send to 1 user at Gmail, but some server doesn't handle the AUTH extension. You need to disable outgoing authentication, unless you're delivering only to MTAs you control.
Is there anything in the Postfix logs that indicated it tried to connect to gmail.com, and the message was rejected? I suspect that there won't be, and that the problem is that you have smtp_user and smtp_pass configured. Then Mailman will use those and the AUTH command to try to authenticate to your Postfix. That can be done, but you need to configure Postfix (not a system user and password) to accept the AUTH command. There may be a way to get Postfix to /etc/passwd to authenticate a user, but I don't know what it is.
1554 Feb 02 06:57:21 2026 (4128778) while connecting to SMTP: 1555 Feb 02 06:59:37 2026 (664714) <176979064563.3611678.6370323034981829398@lists> low level smtp error: [Errno 110] Connection timed out
I'm not sure what's going on with the above two.
The rest of the messages follow the same pattern for different lists.
I'm using port 25 for smtp, I wasn't sure I'll need submission because I'd done that earlier and it didn't seem to change anything, does mailman need submission?
No. submission doesn't make sense for Mailman in most configurations (that is, all the configurations I've ever seen).
Steve
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan