Loss reason 100: Bid was Below Auction Floor
What it means
The bid did not clear bidfloor for the impression.
The exchange reports this code by expanding the ${AUCTION_LOSS} macro in the bid's loss notice URL (lurl). A bidder that does not set lurl never sees it, and never learns why it lost.
What the exchange checked
The exchange compared bid.price with imp.bidfloor. The floor's currency is imp.bidfloorcur, which defaults to USD. A currency listed in the request cur array does not set the floor currency.
What to change
Bid at or above that floor, or skip the impression. When the floor looks impossible, read imp.bidfloorcur before you change the price. A floor of 120 that you meant as yen, sent without JPY, is a 120 USD floor, and every bid under it returns 100. The floor signals page covers where each floor lives on the impression and on a deal.