On 2026-02-20 17:01, Michael Wise via mailop wrote:
It’s throttling.
Any evidence of that? I note Microsoft's own documentation (https://substrate.office.com/ip-domain-management-snds/postmaster/troubleshooting#errors) indicates this kind of situation would receive a different message, e.g.:
421 RP-001 The mail server IP connecting to Outlook.com server has exceeded the rate limit allowed. Reason for rate limitation is related to IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
421 RP-002 The mail server IP connecting to Outlook.com server has exceeded the rate limit allowed on this connection. Reason for rate limitation is related to IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
421 RP-003 The mail server IP connecting to Outlook.com server has exceeded the connection limit allowed. Reason for limitation is related to IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
(not that I expect Microsoft to follow their documentation, but :shrug:) M. -- Michael Brown Civilized Discourse Construction Kit, Inc. https://www.discourse.org/ _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
