Chartboost loss 211 is a missing MRAID crtype, and 1000 through 1003 are Chartboost's own.

Chartboost publishes an OpenRTB-shaped loss table and then breaks it in a few places a bidder has to memorize.

211 is the important break. OpenRTB 211 is an ad-type exclusion. Chartboost 211 means a rewarded non-VAST response was missing bid.ext.crtype set to MRAID playable. 206 is the other break: Chartboost still means a blocked app bundle, which is the OpenRTB 2.5 name. The current OpenRTB list moved that meaning to 215.

5 is Chartboost's wording for an impid that does not match. 102 is a higher bid, and it is the only code on which Chartboost fills the minimum-bid macro, after the seat is enabled for it. 214 is an invalid SKAdNetwork payload. 502 means the bid won and the ad then failed to load.

The 1000s are Chartboost's. 1000 is a crid blocked globally. 1001 is a late bid. 1002 is a raw single quote in burl or ext.imptrackers. 1003 is a tracker URL over 12,000 characters.