nbr 13: Ads.cert Authentication Unavailable

What it means

No ads.cert signature was available to authenticate the request.

A bidder returns nbr on an otherwise empty BidResponse to say why it is not bidding, instead of (or alongside) an HTTP 204. Code 13 is ads.cert authentication unavailable.

What to do about it

The bidder could not verify the seller through ads.txt or ads.cert. Check that your ads.txt is reachable and lists the seller account exactly as the request declares it, and that the sellers.json entries the schain references resolve. These codes are the buyer telling you your trust chain does not check out.

Related

• The full nbr code table and how to debug a bidder that stops bidding
• Loss reason codes: the other half of bid feedback
• The validator rule for responses missing both seatbid and nbr