GoKawiilOutlook.com begins silently bouncing mail from domains lacking DMARC records
Since November 5, 2026, Microsoft's consumer email service has been rejecting a portion of incoming mail from domains that have not published a DMARC DNS record, even when those domains have working SPF and DKIM. Affected senders receive a 550 5.7.1 bounce citing missing SPF/DKIM/DMARC authentication, and Microsoft has not issued any public notice explaining the change.