You've heard Outlook now “requires authentication” but can't tell whether you're affected or compliant.
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What this means
Microsoft's rules (enforced from May 5, 2025) apply to domains sending 5,000+ messages/day to consumer Outlook/Hotmail/Live addresses — with rejection, not spam-foldering, as the penalty. Smaller senders face the same checks in softer form.
How to fix it
Step 1. SPF: published, syntactically valid, under 10 lookups, covers every sending service.
Step 2. DKIM: enabled and signing in every service that sends as your domain.
Step 3. DMARC: published, minimum p=none with rua reporting; SPF or DKIM aligned with your From domain.
Step 4. Hygiene: valid reply-to, working unsubscribe, bounce management, complaint rate under control.
Frequently asked
How long until fixes take effect?
DNS changes propagate within minutes to 48 hours. Mailbox providers pick up the new records on their next check — most senders see bounces stop within a day of correct configuration.
Does this apply if I send fewer than 5,000 emails a day?
Formal enforcement targets bulk senders, but partial authentication already costs you inbox placement at every volume — and spoofing protection matters regardless of how much you send.
Can I just ask my hosting provider to fix it?
Hosting support can add DNS records for you, but they don't know which services send as your domain. You (or a monitoring tool reading your DMARC reports) have to provide that list — that's the actual hard part.
Don't want to babysit DNS records? DMARCKeeper monitors your reports, names every sender, and walks you to full p=reject protection. Start free monitoring →