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
The first thing I’d do is look at the outgoing mail logs. If it’s bouncing 1/3rd of your users, it’s very likely it’s one or two whole domains that are bouncing, probably because your IP has been black listed or you don’t have DKIM set up right or something like that. The outgoing mail logs might tell you that. Also, don’t you get a copy of the “disabling bounce”? I always get one of that when somebody gets bounced off the list. The bounce message itself usually gives you a clue as well - I think it’s in an attachment called email.eml or something like that.
On Thu, May 7, 2026, at 10:39 AM, Stephen Daniel wrote:
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
Mailman-users mailing list -- mailman-users@mailman3.org To unsubscribe send an email to mailman-users-leave@mailman3.org https://lists.mailman3.org/mailman3/lists/mailman-users.mailman3.org/ Archived at: https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/message/...
This message sent to ptomblin@xcski.com
-- Paul Tomblin
Thanks. Looking at one of the notifications, I see this is a DKIM failure.: The response from the remote server was:
550 5.7.9 This mail has been blocked because the sender is unauthenticated. Yahoo requires all senders to authenticate with either SPF or DKIM. Authentication results: DKIM = FAILURE - SPF XXX.org with ip X.Y.Z.W = SUCCESS. See https://senders.yahooinc.com/smtp-error-codes/#authentication-failures for more information. This has worked for a long time. What would suddenly cause DKIM failures?
On Thu, May 7, 2026 at 11:02 AM Paul Tomblin via Mailman-users < mailman-users@mailman3.org> wrote:
The first thing I’d do is look at the outgoing mail logs. If it’s bouncing 1/3rd of your users, it’s very likely it’s one or two whole domains that are bouncing, probably because your IP has been black listed or you don’t have DKIM set up right or something like that. The outgoing mail logs might tell you that. Also, don’t you get a copy of the “disabling bounce”? I always get one of that when somebody gets bounced off the list. The bounce message itself usually gives you a clue as well - I think it’s in an attachment called email.eml or something like that.
On Thu, May 7, 2026, at 10:39 AM, Stephen Daniel wrote:
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
Mailman-users mailing list -- mailman-users@mailman3.org To unsubscribe send an email to mailman-users-leave@mailman3.org https://lists.mailman3.org/mailman3/lists/mailman-users.mailman3.org/ Archived at:
https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/message/...
This message sent to ptomblin@xcski.com
-- Paul Tomblin
Mailman-users mailing list -- mailman-users@mailman3.org To unsubscribe send an email to mailman-users-leave@mailman3.org https://lists.mailman3.org/mailman3/lists/mailman-users.mailman3.org/ Archived at: https://lists.mailman3.org/archives/list/mailman-users@mailman3.org/message/...
This message sent to swd@pobox.com
Stephen Daniel writes
550 5.7.9 This mail has been blocked because the sender is unauthenticated. Yahoo requires all senders to authenticate with either SPF or DKIM. Authentication results: DKIM = FAILURE - SPF XXX.org with ip X.Y.Z.W = SUCCESS. See https://senders.yahooinc.com/smtp-error-codes/#authentication-failures for more information. This has worked for a long time. What would suddenly cause DKIM failures?
I just saw the same thing with all my yahoo subscribers. Yahoo are the worst freemail provider I have come across.
I contacted all my yahoo subscribers. They gave me non-yahoo addresses.
-- Written by Thomas Krichel http://openlib.org/home/krichel on his 22252nd day.
What a mess. My domain used to be managed by domains.google.com, which got sold to Squarespace. I looked at my DNS records on Squarespace and I cannot find anything resembling normal DKIM records.
I do see a CNAME record for _domainconnect.domains.squarespace.com, which seems suspicious. I also see a CNAME record for *randomname* with the value *randomstring.* dv.googlehosted.com.
How any of this ever worked I do not know. I think it is time to move my domain to Cloudflare and set up DKIM from scratch.
On Thu, May 7, 2026 at 11:31 AM Thomas Krichel <krichel@openlib.org> wrote:
Stephen Daniel writes
550 5.7.9 This mail has been blocked because the sender is unauthenticated. Yahoo requires all senders to authenticate with either SPF or DKIM. Authentication results: DKIM = FAILURE - SPF XXX.org with ip X.Y.Z.W = SUCCESS. See https://senders.yahooinc.com/smtp-error-codes/#authentication-failures for more information. This has worked for a long time. What would suddenly cause DKIM failures?
I just saw the same thing with all my yahoo subscribers. Yahoo are the worst freemail provider I have come across.
I contacted all my yahoo subscribers. They gave me non-yahoo addresses.
-- Written by Thomas Krichel http://openlib.org/home/krichel on his 22252nd day.
Stephen Daniel writes:
What a mess. My domain used to be managed by domains.google.com, which got sold to Squarespace. I looked at my DNS records on Squarespace and I cannot find anything resembling normal DKIM records.
Do you mean Squarespace allows you to manage your own DNS records and you're looking at it in the management interface (in which case they should give you a list of all records). Or are you looking for $SELECTOR._domainkey.XXX.org using a DNS lookup application (in which case they may have rotated keys and changed the selector on you)?
I do see a CNAME record for _domainconnect.domains.squarespace.com, which seems suspicious. I also see a CNAME record for *randomname* with the value *randomstring.* dv.googlehosted.com.
I don't see why that would be suspicious. This kind of configuration can be useful when "the server" is a cloud application.
How any of this ever worked I do not know. I think it is time to move my domain to Cloudflare and set up DKIM from scratch.
Generally that's a good idea if you know what you're doing.
Stephen Daniel writes
550 5.7.9 This mail has been blocked because the sender is unauthenticated. Yahoo requires all senders to authenticate with either SPF or DKIM. Authentication results: DKIM = FAILURE - SPF XXX.org with ip X.Y.Z.W = SUCCESS.
That is quite weird -- it says SPF authentication *succeeded*, which should be sufficient. It's possible it's a Yahoo misconfiguration which will fix itself, as far as SPF is concerned. But you should still find out what's going on with DKIM.
Steve
-- GNU Mailman consultant (installation, migration, customization) Sirius Open Source https://www.siriusopensource.com/ Software systems consulting in Europe, North America, and Japan
participants (4)
-
Paul Tomblin -
Stephen Daniel -
Stephen J. Turnbull -
Thomas Krichel