nbr 4: Suspected Non-Human Traffic

What it means

IVT filters flagged the request as likely bot traffic.

A bidder returns nbr on an otherwise empty BidResponse to say why it is not bidding, instead of (or alongside) an HTTP 204. Code 4 is suspected non-human traffic.

What to do about it

The bidder's invalid-traffic filters rejected the request source: crawler user agents, suspected non-human traffic, or data-center IPs. Persistent volume here is a supply-quality conversation, not a protocol bug; check what your device, ip, and user-agent fields actually carry.

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