What is this
BIMI (Brand Indicators for Message Identification) shows your brand logo in the inbox next to authenticated mail. It only works when DMARC is at quarantine or reject. For Gmail and Apple Mail you also need a VMC (Verified Mark Certificate).
Why it matters
BIMI improves brand recognition and open rates, and signals to recipients that the mail genuinely comes from you. Without BIMI, recipients see an empty initial or a generic icon.
How to fix it
TransIP: Host your logo as SVG Tiny PS on an HTTPS URL. Add a TXT in DNS at default._bimi with v=BIMI1; l=https://yourdomain.com/bimi/logo.svg; a=https://yourdomain.com/bimi/vmc.pem.
CloudFlare: Upload the SVG and optional VMC to your hosting or R2. Add a TXT in DNS at default._bimi with the same syntax.
Strato or Antagonist: Upload the BIMI SVG to your web hosting. Add via DNS a TXT at default._bimi.
Other: Make sure DMARC is at quarantine or reject first. Produce an SVG Tiny PS per the BIMI Group spec, host over HTTPS, place TXT at default._bimi.
Verify
dig TXT default._bimi.yourdomain.com +short. Use the BIMI Inspector and send a test mail to Gmail to see whether the logo appears.