nbr 8: Unmatched User

What it means

No usable user ID or cookie match, so the bidder cannot target.

A bidder returns nbr on an otherwise empty BidResponse to say why it is not bidding, instead of (or alongside) an HTTP 204. Code 8 is unmatched user.

What to do about it

The request was fine; the bidder chose not to buy. Unsupported devices, blocked publishers, unmatched users, and frequency caps are demand-side policy. The only sender-side lever is signal quality: complete device and app/site objects and usable identity signals reduce unmatched-user passes.

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