Why did my emails suddenly start going to spam?

Updated 2026-11-01

Short answer: when it's sudden, something changed. The usual causes: a new email or marketing service was added to the SPF record and pushed it over its limit of 10 DNS lookups, so SPF fails for everyone; records were lost when the domain moved host or DNS provider; a DKIM key was removed; DMARC was tightened to quarantine or reject; or a sending address landed on a blocklist.

How to check it yourself

  1. Send yourself a test email and open its headers ("Show original" in Gmail). SPF, DKIM and DMARC should each say PASS.
  2. Look up the domain's SPF record (a TXT record starting v=spf1) and count the lookups, including those inside each include. More than 10 and SPF fails.
  3. Think back: did you add an email service, change host or move DNS around the time it started?

What Preventionlabs shows

The email section of every report counts SPF lookups the way receiving servers do, finds the DKIM signing keys, checks DMARC and whether it's enforced, and checks whether the sending addresses your SPF record names are on the SpamCop blocklist. "Changed since the last report" shows which of these went from fine to a problem. With a read-only Cloudflare token, it also lists DNS changes: which record changed, and when. It reads public DNS records only; it doesn't send or test any email.

Price

Free to sign up, with 2 free reports on each domain. Then US$28 a month for 1,500 credits.

Run your first report free