Cogent had two fiber cuts in Southern California yesterday. It greatly affected our San Diego datacenter, causing all our traffic to flow through our LAX datacenter.
This increase in rate has caused Microsoft/Outlook servers to defer all mail flow (even to our customers who are o365 users): ❯ 2026-09-04T10:28:53+00:00 003.mia postfix-relaycust/smtp[888736]: 4hbt2K63Nxxxxx: to=<xxxx>, relay=xxxx-com.mail.protection.outlook.com[52.101.10.16]:25, delay=77, delays=70/0.13/5.8/0.68, dsn=4.7.500, status=deferred (host xxx-com.mail.protection.outlook.com[52.101.10.16] said: 451 4.7.500 Server busy. Please try again later from [199.89.3.6]. (S77714) [BN2PEPF000055E1.namprd21.prod.outlook.com 2026-09-04T10:28:53.346Z 08DF0900FB158D96] (in reply to end of DATA command)) Our San Diego center is back, but the flood of mail returning to it has caused the same issue. We're an email filtering service, not a bulk mailer of any type. We do selective outbound for regular business customers (not bulk, not transactional) - we just really need to relay inbound email to our customers and for their normal business outbound mail to get out. I've submitted a request via SNDS, but I don't know if a human will see it and intervene, and this is urgent for our customers. Can anyone put me in touch with a Microsoft contact who could possibly intervene? Thanks- Tom _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
