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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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Griffo's avatar
Griffo
Brass Contributor
Jul 04, 2025

I believe this has had the un-intended effect of blocking all inbound mail from high-volume senders to ANYONE with a .NAME domain. 
I doubt many people at Microsoft have even heard of the .name 3LD's that were launched in 2003. Basically anyone could buy their name - so freddy.mercury.name came with a free email forwarding service hosted by Verisign. You give everyone your email of freddy@ mercury.name and the Verisign MX forwarders will forward to your chosen email provider. However this breaks SPF as they don't do ARC.

Microsoft need to white-list the Versign .name fowarders but i've spent 3 days going in circles with their outsourced tech support to no result because none of them can even understand the problem "please add the sender to your safe list"

  • Cdary's avatar
    Cdary
    Copper Contributor
    Jul 04, 2025

    For high volume senders, Microsoft requires validation of both SPF and DKIM, but only one of them needs to be aligned with the Header-From domain. If the forwarding service uses SRS and doesn't break DKIM, once the email is forwarded, it will have SPF pass & unaligned and DKIM pass & aligned, which is sufficient for inbox delivery.

    Forwarding services needs to use SRS.