- Mailman-users - lists.mailman3.org

Generic Cannot connect to SMTP server error, no outgoing smtp connections
by Stefan Bauer June 4, 2026

June 4, 2026

Dear Users, I'm debugging since several days a mailman3 installation and can not get mailman to deliver mails to list members. Mailman logs Cannot connect to SMTP server, however the server is listening, but i see no connection attempts. In queue/out, i see changing files all the time: drwxrwx--- 2 mailman nogroup 4.0K Jun 4 13:04 . drwxr-xr-x 15 mailman nogroup 4.0K Jun 4 08:22 .. -rw-rw---- 1 mailman nogroup 6.1K Jun 4 12:22 1780575734.9281623+0ad5f564c9fc5f27750a09b948f3480d9047cbaa.pck.tmp -rw-rw---- 1 mailman nogroup 6.1K Jun 4 13:04 1780578250.2070453+752ca17af5c64af7aab5f0fc61ac2ea28b091825.bak 038b90c74d8d:/opt/mailman/var/queue/out# ls -alh total 24K drwxrwx--- 2 mailman nogroup 4.0K Jun 4 13:04 . drwxr-xr-x 15 mailman nogroup 4.0K Jun 4 08:22 .. -rw-rw---- 1 mailman nogroup 6.1K Jun 4 12:22 1780575734.9281623+0ad5f564c9fc5f27750a09b948f3480d9047cbaa.pck.tmp -rw-rw---- 1 mailman nogroup 6.1K Jun 4 13:04 1780578250.7552953+6350a013583657c317c0a64b9cf2039dca645974.bak 038b90c74d8d:/opt/mailman/var/queue/out# SMTP/DEBUG-Log is flooded with over and over same attempts: ==> /opt/mailman/core/var/logs/smtp.log <== Jun 04 13:04:46 2026 (26) Using agent: <mailman.mta.deliver.Deliver object at 0x79ed98555310> Jun 04 13:04:46 2026 (26) IndividualDelivery to: cubewerk(a)gmail.com ==> /opt/mailman/core/var/logs/debug.log <== Jun 04 13:04:46 2026 (31) [VirginRunner] starting oneloop Jun 04 13:04:46 2026 (31) [VirginRunner] ending oneloop: 0 Jun 04 13:04:46 2026 (26) [OutgoingRunner] finishing filebase: 1780578286.711373+091038a49a00758fdd2ba5265714e2fa31ea4843 Jun 04 13:04:46 2026 (26) [OutgoingRunner] doing periodic Jun 04 13:04:46 2026 (26) [OutgoingRunner] committing transaction Jun 04 13:04:46 2026 (26) [OutgoingRunner] checking short circuit Jun 04 13:04:46 2026 (26) [OutgoingRunner] ending oneloop: 1 Jun 04 13:04:46 2026 (26) [OutgoingRunner] starting oneloop Jun 04 13:04:46 2026 (26) [OutgoingRunner] processing filebase: 1780578286.7329357+2ec378350ee99307adc287fc8727fb9120a385d3 Jun 04 13:04:46 2026 (26) [OutgoingRunner] processing onefile Jun 04 13:04:46 2026 (26) [outgoing] <function deliver at 0x79ed98b85d00>: <gxZS.-LyKCSHn9UWsyVepCakA9g(a)flTQyy2_BUC0KFtMliiieCkabFXP1SdNnP1xIyNQp-k.xz> ==> /opt/mailman/core/var/logs/smtp.log <== Jun 04 13:04:46 2026 (26) Using agent: <mailman.mta.deliver.Deliver object at 0x79ed98a43bf0> Jun 04 13:04:46 2026 (26) IndividualDelivery to: cubewerk(a)gmail.com If i restart the docker-core container, i see a single time the error "Cannot connect to SMTP server 172.17.0.1 on port 587". my config: [runner.retry] sleep_time: 10s [webservice] hostname: 172.18.0.2 port: 8001 admin_user: restadmin admin_pass: restpass configuration: /etc/gunicorn.cfg [mta] incoming: mailman.mta.postfix.LMTP outgoing: mailman.mta.deliver.deliver lmtp_host: 172.18.0.2 lmtp_port: 8024 smtp_host: 172.17.0.1 smtp_port: 587 smtp_user: smtp_pass: smtp_secure_mode: starttls smtp_verify_hostname: false smtp_verify_cert: false configuration: /etc/postfix-mailman.cfg [logging.smtp] level: debug [logging.error] level: debug [logging.debug] level: debug [archiver.mail_archive] enable: no configuration: /opt/mailman/mail_archive_dummy.cfg [archiver.hyperkitty] class: mailman_hyperkitty.Archiver enable: yes configuration: /etc/mailman-hyperkitty.cfg Any helps is greatly appreciated. thank you. Stefan

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Kind of off-topic, but Mailman related
by Paul Tomblin May 30, 2026

May 30, 2026

I back up my server using "borg" to send it to a different server. I keep 7 dailies, 4 weeklies and 6 monthlies. When I used Mailman 2, my borg backup size stabilized and never seemed to grow much. But since switching to Mailman 3, my backup size has been growing, seemingly without bounds, even though the amount of disk space I'm using on the Mailman server isn't growing much. I suspect this might be because of the way it's storing stuff in PostgreSQL instead of in the file system is fooling borg's deduplication methodology. Does anybody else have any experience with borg and Mailman 3? Should I exclude postgreSQL from the backup and do a separate pg_dumpall? -- Paul Tomblin

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Thank you for the tips a year ago! Please help me gather other use-cases
by Rodrigo Camacho May 29, 2026

May 29, 2026

Hello fellow mailing list users and enthusiasts. About a year ago I posted this thread: https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/thread/… We are now using mailing lists as our only form of collaboration. Overall, the change has been super positive. We have become more productive and importantly our quality of life has increased. So much so, that I have built a site explaining some of the changes we have made to help other entrepreneurs get control of their lives by spending less money and time on specialized SaaS tools and sticking to standards. I have posted my particular use-case here: https://standardit.org/lanao.html I am posting this because there might be some interesting use cases amongst the users of this list. I aim at adding various use cases so that more business owners can identify themselves and think that this change is possible. If you think your use case could be of use, feel free to add here. I will include it in the site. Rodrigo succulentoats.com

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Residual signature?
by Paul Tomblin May 28, 2026

May 28, 2026

One of my mailing lists that I converted over from my Mailman 2 instance doesn’t get used much. Well, something momentous happened and it got several messages overnight, and I noticed something odd about them. Every one has the signature “— \nAdministration:”. This looks like a fragment of the signature that Mailman 2 used to put on them, but I can’t figure out where it’s configured. There’s nothing in the list or domain template list that would do that. How can I stop it doing that? -- Paul Tomblin

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Trip report -- setting up mailman3 in gcloud
by Stephen Daniel May 24, 2026

May 24, 2026

Mailman people -- I've been running mailman3 in production in Google's cloud for about 4 years now. Recently I started seeing many bounces from members who subscribe from yahoo, aol, bellsouth, or verizon. The bounces were triggered by DKIM failures. DKIM failures in my setup are apparently not new. Some spelunking revealed I've had outbound DKIM failures for years. It is possible my system has never properly signed outbound emails. But now it matters to these email providers. I decided to spin up a dev/test instance. I installed mailman3 from scratch in a venv environment on Debian 12. I used these excellent instructions: https://docs.list.org/en/latest/install/virtualenv.html#virtualenv-install I got this: GNU Mailman 3.3.10 (Tom Sawyer) Python 3.11.2 (main, Apr 8 2026, 01:58:00) [GCC 12.2.0] What I learned (relearned from 4 years ago): - Getting mailman up is easy. - The hard part is getting traffic in and out. Postfix is complicated to set up in this environment. Getting all the DNS and multiple layers of proxies set up to access Postorius/Django/Gunicorn is not simple. - I took lots of snapshots along the way. I used those snapshots to back out of a couple of dead ends. Highly recommended. I have only one open issue. Shortly after I start mailman I get this warning: /opt/mailman/venv/lib/python3.11/site-packages/falcon/request.py:2483: DeprecatedWarning: The RequestOptions.auto_parse_form_urlencoded option is deprecated. Please use Request.get_media() to consume the submitted URL-encoded form instead. warnings.warn( I am ignoring this. Is there something I should do about this? In the end, after experimenting with many possible solutions (including installing openDKIM), the solution was simple. I added this line to my mailman.cfg: remove_dkim_headers: yes Once the DKIM headers were removed, my outbound SMTP relay happily signs the emails and all is well. (Or it least it is after hours spent learning how to configure the outbound relay properly.) Someday soon I need to completely reinstall my production environment, but for now, I'm continuing on. Thanks to this community for all you do. -- Stephen Daniel

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Howto discard all pending unsubscription requests in a list?
by Andreas Vetter May 20, 2026

May 20, 2026

Hi, a moderator managed to remove almost 2000 members from a list. Luckily unsubscription is set to moderated. Is there a script to discard all tose requests and get the members back on the list? I found https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/ thread/UB6HHD4Q2GQ5XSDDXWMKJHTTADXFT46L/#DNV6AU4E3EBS2JUTZQD64GBJM7JHT3WP but this is meant for single request and involves manual finding a token. My python skills are not existent, so I don't know how to use that for my situation. Any hints appreciated. TIA, Andreas

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Missing bits of French translation
by iMark May 13, 2026

May 13, 2026

Hi, I have a list set with "French" as its preferred language. The default emails such as the Confimation and Welcome get sent French. My browser (Chrome) has its default language set as French, and my PC's region and language are set as French. When I view the list's "Info" Postorius page I see some parts translated ... 1. Menu and button words are translated okay. eg: ENGLISH: Sign In FRENCH: S'identifier 2. Page heading words are translated okay. eg: ENGLISH: Subscription / Unsubscription FRENCH: Abonnement / désabonnement 3. Page text fails. eg. ENGLISH: You have to sign in to visit the archives of this list. FRENCH: Is in English. Looking at the .po file ... /opt/mailman/venv/lib/python3.11/site-packages/mailman/messages/fr/LC_MESSAGES/mailman.po "PO-Revision-Date: 2024-06-25 17:09+0000\n" None of the msgid strings for the 3 examples appear in the mailman.po file. So, as some strings are translated and others not (yet none appear in the mailman.po file), I'm thinking that either there is another translation file somewhere for Postorius that needs updating, or the missing msgid s were not included in the original .pot file. Am I on the right track?

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How to debug bounces?
by Stephen Daniel May 7, 2026

May 7, 2026

Colleagues -- I run a small mailman3 server with perhaps 10 lists. All the lists are small. Over the past two days about a third of the users in my most active list have been disabled by bounces. I assume the problem is with my setup, not with all of those users. How do I debug this? Can I see the text of any of the bounce messages to understand why the emails bounced? This issue might stem from my running somewhat old software. Currently running mailman 3.3.5. Thanks! -- Stephen Daniel

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How to build docs and how to contribute documentation
by mailman26＠xse.com May 6, 2026

May 6, 2026

I have mailman 3 working with sendmail (FreeBSD system) and when I was setting this up I found the "Sendmail" section of the docs to be somewhat thin: https://docs.mailman3.org/projects/mailman/en/latest/src/mailman/docs/mta.h… It points to two different versions of the mailertable hack: https://gist.github.com/Maeglin73/72eb5b1e4ee66a383c2aa454726be9a5 https://gitlab.com/mailman/mailman/-/work_items/307#note_632495542 I got a version of this to work but was not satisfied because it required hacking either mailman or sendmail config to cleanup the domain in the recipient address. Eventually I realized that "mailman inject" could be use in very similar way to how mailman 2 lists work with sendmail (alias pipe to a command). This provides a path to submit messages without using LMTP. First, how does one build the mailman 3 documentation? I am mildly experienced with sphinx so the actual changes are not an issue. But I was only able to build mailman-suite-doc documentation; it wasn't obvious to me now to build docs for mailman core (let alone an of the other pages I find on docs.mailman3.org) Next, how are code and documentation contributions submitted for consideration? I'm a lot more familiar with github than gitlab and know how to fork but it didn't look like I would be able to submit a pull request. Craig

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captcha for subscription and account registration forms
by Johannes Rohr May 2, 2026

May 2, 2026

Dear all, in mailman installed in venv is there really no canonical way of integrating a captcha into postorius' subscription and account registration forms? We are increasingly getting hammered by spambots, and a captcha would seem like a simple and effective solution. Thanks for any suggestions! Johannes

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