Symptoms#
- Messages landing in spam despite previously good placement
- Bounces mentioning policy, authentication, or reputation
- Provider dashboards showing a drop in reputation or authentication pass rate
Diagnosis steps#
- Confirm the configuration is live: query DNS from an external resolver and check the sending platform's settings page.
- Send to a seed mailbox and read the full headers, especially Authentication-Results.
- Compare the domains in From, Return-Path, and DKIM d= for alignment.
- Check provider dashboards (Google Postmaster Tools, Microsoft SNDS) for reputation and error rates.
- Review recent changes: new vendors, DNS edits, list imports, volume spikes.
Likely causes#
- Image-only emails.
- Tracking links on a shared domain used by spammers.
Fix and re-verify#
- Keep a healthy text-to-image ratio and always include a plain-text part.
- Link to your own domain; avoid shorteners and tracking domains with poor reputation.
- Make link text match the destination.
- Test rendering and spam scores before sending.
Frequently asked questions#
Are spam trigger words still a thing?
Much less than a decade ago. Modern filters are statistical and reputation-weighted. Deceptive intent matters more than any single word.