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#
- Publishing BIMI while DMARC is still at p=none; providers ignore the record.
- Uploading a standard SVG exported from a design tool; it must be the Tiny PS profile with no scripts or external references.
- Hosting the logo on a non-HTTPS URL or behind a redirect.
Fix and re-verify#
- Reach DMARC p=quarantine (pct=100) or p=reject on the sending domain.
- Produce your logo as an SVG Tiny 1.2 Portable/Secure file, square, centered, with a solid background.
- Obtain a VMC or CMC from an approved certificate authority if you want display in Gmail and Apple Mail.
- Publish default._bimi.yourdomain.com with l= (logo URL) and a= (certificate URL).
- Validate with a BIMI inspector and send a test to Gmail, Yahoo, and Apple seed accounts.
Frequently asked questions#
Does BIMI work without a VMC?
Yahoo and Fastmail display BIMI logos with DMARC enforcement alone. Gmail and Apple require a VMC or CMC.
What image format does BIMI require?
SVG Tiny 1.2 Portable/Secure. No PNG, JPG, or standard SVG.
Does BIMI improve deliverability?
Not directly. Its prerequisite, DMARC enforcement, does. The logo mainly lifts engagement and trust.