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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
Version 4.0
awareness & training
email protection basics
Xean45's avatar
Xean45
Copper Contributor
Dec 03, 2025

This new security is unworkable. I'm trying to do everything right, but still getting rate limited. Why must Microsoft always make things so overly complicated that they don't work without enrolling in a two month course? "The mail server [##.##.#.##] has been temporarily rate limited due to IP reputation." cannot seem to be avoided.