Loss reason 203: Creative Filtered - Size Not Allowed

What it means

Creative dimensions did not fit 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 to do about it

The 200-series means the exchange's creative policy rejected the ad after the auction logic: size, format, security, category, attribute, or store exclusions, or a creative still pending review. Compare what your adm actually contains against what the imp offered (the validator's markup-vs-mtype and markup-vs-imp checks catch format mismatches), and pre-sync creative approvals with exchanges that require review.

Related

• The full loss reason table
• ${AUCTION_MIN_TO_WIN}: the price-discovery companion macro
• Loss reason 201: Creative Filtered - Pending Processing by Exchange
• Loss reason 202: Creative Filtered - Disapproved by Exchange
• Loss reason 204: Creative Filtered - Incorrect Creative Format
• Loss reason 205: Creative Filtered - Advertiser Exclusions