securityonline.info
Outlook DMARC Email Rejection Policy Bounces Unsigned Messages
Email security provider MailRoute recently detected a significant shift in inbound filtering across Microsoft consumer mailboxes. Specifically, starting in early November 2026, Outlook.com began rejecting messages originating from custom domains lacking DMARC records. Consequently, routine transactional emails and low-volume communications face unexpected delivery failures. This enforcement impacts organizations dispatching order confirmations, verification codes, and customer support notifications. Therefore, administrators must adapt their transmission protocols to preserve inbox access.