On Tue, Sep 8, 2026 at 5:39 PM Brie Yoder <[email protected]> wrote:
> On Sep 8, 2026, at 9:26 a, Washington Odhiambo <[email protected]> wrote: > > > I have some clients using them so this interests me. > > > You should be happy you have no issues! Don’t tempt fate. > > Can you please share the content of the NDRs from your bounces - both from > the ML and the personal email you sent to them? Of course obfuscate > whatever you consider sensible. > > > I spoke too soon without double-checking - mailmanlists.net does not have > their email hosted with MS 365 - they use migadu.com. > > Bounce from my email to [email protected]: > > *Delivery has failed to these recipients or groups:* > > [email protected] ([email protected]) > <[email protected]> > Your message wasn't delivered. Despite repeated attempts to deliver your > message, a connection to the remote server couldn't be made. > > Contact the recipient by some other means (by phone, for example) and ask > them to tell their email admin that it appears that your email system is > unable to connecto their email system. Give them the error details shown > below. It's likely that the recipient's email admin is the only one who can > fix this problem. > > For more information and tips to fix this issue see this article: > https://go.microsoft.com/fwlink/?LinkId=389361. > > > *Diagnostic information for administrators:* > > Generating server: MW4PR12MB8611.namprd12.prod.outlook.com > <http://mw4pr12mb8611.namprd12.prod.outlook.com/> > Receiving server: MW4PR12MB8611.namprd12.prod.outlook.com > <http://mw4pr12mb8611.namprd12.prod.outlook.com/> > > [email protected] > 9/8/2026 4:31:59 AM - Server at MW4PR12MB8611.namprd12.prod.outlook.com > <http://mw4pr12mb8611.namprd12.prod.outlook.com/> returned '550 5.4.317 > Message expired, cannot connect to remote server(451 4.4.8 MX hosts of ' > mailmanlists.net' failed MTA-STS validation.)' > 9/8/2026 4:21:59 AM - Server at mailmanlists.net (0.0.0.0) returned '450 > 4.4.317 Cannot establish session with remote server [Message=451 4.4.8 MX > hosts of 'mailmanlists.net' failed MTA-STS validation.] > [LastAttemptedServerName=mailmanlists.net] [ > BL6PEPF0001E442.namprd02.prod.outlook.com > <http://bl6pepf0001e442.namprd02.prod.outlook.com/> 2026-09-08T04:21:59.309Z > 08DF0B0055FEBFFE](451 4.4.8 MX hosts of 'mailmanlists.net' failed MTA-STS > validation.)' > > > > > > Did something change in your DNS settings recently? > > PS: Your inline responses are quite difficult to read. Which MuA is that you use? Anyway, you did mention that they are hosted by MS365. I don't think that is correct. It's the MS365 servers that gave you the NDR after they failed to deliver your email to mailmanlists.net: Not sure if migadu.com is owned by the Redmond guys. ``` 19:43 wash@eu:~$ host -tmx mailmanlists.net mailmanlists.net mail is handled by 10 aspmx1.migadu.com. mailmanlists.net mail is handled by 20 aspmx2.migadu.com. 19:43 wash@eu:~$ ``` Anyway, I have sent them an email (from this very address I am using here) complete with the NDR, requesting them to get in touch with you. Their support team knows me so I hope they will reach out. -- Best regards, Odhiambo WASHINGTON, Nairobi,KE +254 7 3200 0004/+254 7 2274 3223 In an Internet failure case, the #1 suspect is a constant: DNS. "Oh, the cruft.", egrep -v '^$|^.*#' ¯\_(ツ)_/¯ :-) [How to ask smart questions: http://www.catb.org/~esr/faqs/smart-questions.html] ------------------------------------------------------ Mailman-Users mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/mailman-users.python.org/ Mailman FAQ: http://wiki.list.org/x/AgA3 Security Policy: http://wiki.list.org/x/QIA9 Searchable Archives: https://www.mail-archive.com/[email protected]/ https://mail.python.org/archives/list/[email protected]/ Member address: [email protected]
