Blog Post
Strengthening Email Ecosystem: Outlook’s New Requirements for High‐Volume Senders
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"
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.