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Microsoft Defender for Office 365 Blog
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Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders

Puneeth's avatar
Puneeth
Icon for Microsoft rankMicrosoft
Apr 02, 2025

This applies to Outlook.com - our consumer service, which is supporting hotmail.com live.com and outlook.com consumer domain addresses.

April 29th Update - Changes have been made to the action take on messages that do not meet requirements, please see details below. Introduction In an era where email remains one of the most widel...
Updated Apr 30, 2025
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awareness & training
email protection basics
piskigp's avatar
piskigp
Copper Contributor
May 16, 2025

Hello,
With the new Microsoft standards, I'm experiencing a bounced error because it says SPF=Fail. I've reviewed the records and they're correct.It's inside an SPF include.

When I send an email through that same IP, it returns spf=pass and then randomly displays spf=fail when sending another message to another user.
It seems random. Why?
Has anyone seen the same thing?
Thanks for the help and comments!