Definitely not just you, and definitely not just today... Microsoft
shenanigans have been going on since January. They come in waves. The S3150
bounces that the heated thread was about here last week seems to have calmed
(for now), but various rate limiting (S775, S3114 etc), and 451 4.7.500 Server
busy. Please try again later from [xxx.xx.xxx.xxx]. (AS750) have been insane.
This even affects Validity Certified IPs after AS750 delays - I opened a ticket
and Microsoft Support said "These IPs are certified. For any deliverability
problems please contact Validity."
Fun times :)
AK
On Monday, February 23, 2026 at 03:57:15 PM EST, Jarland Donnell via mailop
<[email protected]> wrote:
I just wanted to poke around and ask if anyone else was seeing an
increase in behavior like this today from MS:
451 4.7.650 The mail server [136.175.108.47] has been temporarily rate
limited due to IP reputation. For e-mail delivery information, see
https://aka.ms/postmaster (S775) [Name=Protocol Filter
Agent][AGT=PFA][MxId=11BCD799F8C0D17A]
[DB1PEPF00050A01.eurprd03.prod.outlook.com 2026-02-23T20:36:05.976Z
08DE6BCD08E3CD4A]
I mean, we fight harder against outbound spam than any ESP I've ever
witnessed, to the point that spammers frequently call me a "Nazi." No
significant number of complaints over their FBL, but every one is
actioned. I'll accept if it's just me, but it would be nice to hear it's
not just me.
_______________________________________________
mailop mailing list
[email protected]
https://list.mailop.org/listinfo/mailop
_______________________________________________
mailop mailing list
[email protected]
https://list.mailop.org/listinfo/mailop
