Microsoft Email Security: Mandatory SPF, DKIM & DMARC for High-Volume Senders
As email security threats rise, Yahoo, Gmail, and now Microsoft enforce a new email sender policy that mandates using SPF, DKIM, and DMARC for high-volume senders routing their emails to outlook.com, live.com, hotmail.com, and other Microsoft services.
Starting from May 5, 2025, this policy will affect any domain that sends over 5,000 emails daily to Microsoft recipients. Failure to comply will mean your emails will be sent to the Junk folder and in the future, non-compliant emails will be rejected.