Starting May 5, Microsoft will require DMARC.

Check if your domain is compliant.

The Skysnag Blog

"Learn about Sender Policy Framework (SPF), an email authentication protocol that prevents email spoofing by verifying authorized senders for a domain."
October 11, 2023

What is Sender Policy Framework (SPF)

What is SPF SPF(Sender Policy Framework) is an email authentication protocol that domain admins deploy to prevent spammers from spoofing their domain. […]