Chartboost RTB error 1003: Tracker URL longer than 12K
What Chartboost says
A burl or ext.imptrackers URL is longer than 12,000 characters.
Chartboost reports this integer in the ${AUCTION_LOSS} macro on the bid's lurl. A search for Chartboost RTB error 1003 is this code.
What to change
Shorten the tracker URL to 12,000 characters or less.