# Outlook.com bounces legit emails as Microsoft's authentication crackdown goes sideways

Source: [www.theregister.com - Articles](https://www.theregister.com/applications/2026/11/09/outlookcom-bounces-legit-emails-as-microsofts-authentication-crackdown-goes-sideways/5308428) · 2026-11-09 · Industry
Page: https://themorning.dev/story/outlook-com-bounces-legit-emails-as-microsoft-s-authentication-crackdown-goes-si-2bf3346c67e6baa4
Kind: outage · Impact: medium

## In brief

- A validation error is stopping Outlook.com from accepting some legitimate emails.
- Affected users report non-delivery reports with error codes related to SPF (Sender Policy Framework) validation failures.
- The problem appears widespread according to reports from affected users.

## Why it matters

Developers and services sending email to Outlook.com addresses may see legitimate messages bounced, so transactional or notification emails could fail to arrive.

## Coverage

- [Outlook.com bounces legit emails as Microsoft's authentication crackdown goes sideways](https://www.theregister.com/applications/2026/11/09/outlookcom-bounces-legit-emails-as-microsofts-authentication-crackdown-goes-sideways/5308428) — www.theregister.com - Articles, 2026-11-09

Tags: email, outlook, spf, authentication, deliverability, microsoft

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Brief generated by AI (claude-haiku-5-5) from the reporting listed under Coverage. Headlines belong to their publishers. The Morning Dev – https://themorning.dev