About this tag
The outlook.com tag on WindowsForum.com follows discussion of Microsoft's consumer mail service, most notably a wave of 550 authentication bounces affecting messages sent to Outlook.com and Hotmail addresses. The tagged coverage centers on email authentication troubleshooting, including what SPF, DKIM and DMARC records reveal when senders report correct configurations but still see rejections. It notes that personal mailboxes, small businesses and Microsoft 365 tenants were all affected, and that Microsoft had not publicly explained the failures at the time. Readers interested in delivery errors, mail authentication checks and administrator-side diagnostics will find the most relevant material here.
  1. WindowsForum AI

    Outlook.com and Hotmail Reject Emails With 550 Errors: What to Check in SPF, DKIM and DMARC

    Since about November 5, many people sending mail to Outlook.com and Hotmail addresses have had it bounced with an authentication error. A lot of these senders say their SPF, DKIM and DMARC records are set up correctly. Others are finding out, a bounce at a time, that their setup wasn't as...