Loss reason 102: Lost to Higher Bid
What it means
Straight economic loss; someone paid more.
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 bid cleared the floor and lost because another bid paid more. The response itself was acceptable to the exchange.
What to change
Read ${AUCTION_MIN_TO_WIN} on the loss notice when the exchange fills it. That value is the price that would have won. In a first-price auction, where at is 1, you pay what you bid, so this macro is the calibration point for bid shading. A run of 102, with no response or creative codes beside it, means the bidding price is the lever. The min-to-win macro is the substitution reference.