This is a hard limit (30 emails per minute, 1800 per hour per mailbox) built into O365. Microsoft reccomends using 3rd party bulk mail oroviders like MailChimp. O365 mailboxes are not really suitable for mass emailing, and you can only relay through a desgnated mailbox, iirc.
This isn’t fixable with O365 as the relay host afaik. If the list server can be made public facing so that Postfix manages outgoing email outright (a lot more work because its’ another public-facing server, along with any security implications) We use O365, but our SMTP is handled by Barracuda which provides anti-spam, anti impersonation and other services, and we can exempt specific hosts/addresses from these limits with that. On Aug 2, 2022, at 7:49 AM, Stephen J. Turnbull <stephenjturnb...@gmail.com<mailto:stephenjturnb...@gmail.com>> wrote: Francis Jayakanth via Mailman-Users writes: I'm told that there are per minute and per hour restrictions of 30 and 1800 emails respectively (inbound and outbound) on o365. I'm not sure what "limit of 30 emails/minute" means. In the below, I am going to assume it means "addresses to be delivered." The other meaning I could imagine would be "connections", which would make it much easier to comply (as long as you have a few "giant" destinations like Gmail and Yahoo). -- Bruce Johnson University of Arizona College of Pharmacy Information Technology Group Institutions do not have opinions, merely customs ------------------------------------------------------ Mailman-Users mailing list -- mailman-users@python.org To unsubscribe send an email to mailman-users-le...@python.org 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/mailman-users@python.org/ https://mail.python.org/archives/list/mailman-users@python.org/