Type Research & news
Microsoft
Outlook.com bounces legit emails as Microsoft's authentication crackdown goes sideways
1 source
At a glance
Low
MonitorNo fixed deadline
Evidence-weighted, not popularity
Why Low
Low rather than Medium: UK relevance is 40 of 100, little UK-specific signal so far.
Briefing
- IT leaders should review email authentication settings to ensure legitimate emails are not being blocked by Outlook.com.
Next steps
Monitor- For awareness — no fixed action deadline for this reporting
- Outlook.com is experiencing issues with email authentication that may affect senders with missing DMARC or unstable SPF configurations.
Next steps
Monitor- No immediate technical action — track if your estate depends on the products or vendors discussed
Summary
- Outlook.com is bouncing legitimate emails due to issues with Microsoft's authentication measures.
- Emails from senders with missing DMARC or unstable SPF settings may be flagged as suspicious by Outlook.com.
Read the original reportThe Register Security(opens in a new tab)
19 reports
Part of Multiple Microsoft vulnerabilities reported
Pulse
Last change 41m ago · Next recheck 10 Nov 2026, 14:22 UK time
- Story9 Nov 2026, 14:22 UK time · 41m ago
Linked reporting from The Register Security (independent original reporting).
Read source (The Register Security)
1 entry so far. The timeline chart appears once this story has more history.
Sources
- The Register SecurityNews
Outlook.com bounces legit emails as Microsoft's authentication crackdown goes sideways
How we know
Statements extracted from sources. Higher confidence means stronger corroboration.
- ClaimedHeadline60% confidence
Outlook.com bounces legit emails as Microsoft's authentication crackdown goes sideways
- ProbableSummary fact75% confidence
Missing DMARC or wobbly SPF means your mail may be treated as suspicious