Microsoft email checks block legitimate messages from some senders

Outlook.com and other Microsoft consumer email services have been rejecting some legitimate messages after changes to email authentication checks. The apparent service issue matters because even small senders may find their emails blocked, with vague error messages and no clear explanation from Microsoft.

Users have reported bounces tied to SPF failures or missing DMARC records, though some say their settings were compliant. Microsoft’s guidance requires SPF to pass, DKIM to validate the message, and DMARC to use at least `p=none` and align with SPF or DKIM; resend attempts may sometimes succeed. A support forum moderator called the incident a “service degradation”, and Microsoft said it was investigating.