For what it's worth, not an isolated instance. (Probably good; general problems tend to be easier to diagnose and fix.)
https://api.chess.com/pub/player/chidori_boruto/games/archives
{"archives":["https://api.chess.com/pub/player/chidori_boruto/games/2017/07","https://api.chess.com/pub/player/chidori_boruto/games/2017/08","https://api.chess.com/pub/player/chidori_boruto/games/2017/09","https://api.chess.com/pub/player/chidori_boruto/games/2017/10","https://api.chess.com/pub/player/chidori_boruto/games/2017/11","https://api.chess.com/pub/player/chidori_boruto/games/2017/12","https://api.chess.com/pub/player/chidori_boruto/games/2018/01"]}
https://api.chess.com/pub/player/chidori_boruto/games/2017/11
{"message":"Entity of type 'Chess\\WebBundle\\Entity\\LiveTournament' for IDs tournamentId(905759) was not found","code":0}
Since I'm looking for an archive and not a tournament, that's probably a Clue. Same error in my previous post, so the problem whatever it is looks consistent. (Again, probably good! I hate the times one symptom has two or more issues behind it!)
Came across this today:
https://api.chess.com/pub/player/baldemorski/games/archives
{"archives":["https://api.chess.com/pub/player/baldemorski/games/2012/01","https://api.chess.com/pub/player/baldemorski/games/2012/02","https://api.chess.com/pub/player/baldemorski/games/2012/03","https://api.chess.com/pub/player/baldemorski/games/2012/04","https://api.chess.com/pub/player/baldemorski/games/2012/05","https://api.chess.com/pub/player/baldemorski/games/2012/06","https://api.chess.com/pub/player/baldemorski/games/2012/07","https://api.chess.com/pub/player/baldemorski/games/2012/08","https://api.chess.com/pub/player/baldemorski/games/2012/09","https://api.chess.com/pub/player/baldemorski/games/2012/10","https://api.chess.com/pub/player/baldemorski/games/2012/11","https://api.chess.com/pub/player/baldemorski/games/2012/12","https://api.chess.com/pub/player/baldemorski/games/2013/01","https://api.chess.com/pub/player/baldemorski/games/2013/02","https://api.chess.com/pub/player/baldemorski/games/2013/03","https://api.chess.com/pub/player/baldemorski/games/2013/04","https://api.chess.com/pub/player/baldemorski/games/2013/05","https://api.chess.com/pub/player/baldemorski/games/2013/06","https://api.chess.com/pub/player/baldemorski/games/2013/07","https://api.chess.com/pub/player/baldemorski/games/2013/08","https://api.chess.com/pub/player/baldemorski/games/2013/09","https://api.chess.com/pub/player/baldemorski/games/2013/10","https://api.chess.com/pub/player/baldemorski/games/2013/11","https://api.chess.com/pub/player/baldemorski/games/2013/12","https://api.chess.com/pub/player/baldemorski/games/2014/01","https://api.chess.com/pub/player/baldemorski/games/2014/02","https://api.chess.com/pub/player/baldemorski/games/2014/03","https://api.chess.com/pub/player/baldemorski/games/2014/04","https://api.chess.com/pub/player/baldemorski/games/2014/05","https://api.chess.com/pub/player/baldemorski/games/2014/06","https://api.chess.com/pub/player/baldemorski/games/2014/07","https://api.chess.com/pub/player/baldemorski/games/2014/08","https://api.chess.com/pub/player/baldemorski/games/2014/09","https://api.chess.com/pub/player/baldemorski/games/2014/10","https://api.chess.com/pub/player/baldemorski/games/2014/11","https://api.chess.com/pub/player/baldemorski/games/2014/12","https://api.chess.com/pub/player/baldemorski/games/2015/01","https://api.chess.com/pub/player/baldemorski/games/2015/02","https://api.chess.com/pub/player/baldemorski/games/2015/03","https://api.chess.com/pub/player/baldemorski/games/2015/04","https://api.chess.com/pub/player/baldemorski/games/2015/05","https://api.chess.com/pub/player/baldemorski/games/2015/06","https://api.chess.com/pub/player/baldemorski/games/2015/07","https://api.chess.com/pub/player/baldemorski/games/2015/08","https://api.chess.com/pub/player/baldemorski/games/2015/09","https://api.chess.com/pub/player/baldemorski/games/2015/10","https://api.chess.com/pub/player/baldemorski/games/2015/11","https://api.chess.com/pub/player/baldemorski/games/2015/12","https://api.chess.com/pub/player/baldemorski/games/2016/01","https://api.chess.com/pub/player/baldemorski/games/2016/02","https://api.chess.com/pub/player/baldemorski/games/2016/03","https://api.chess.com/pub/player/baldemorski/games/2016/04","https://api.chess.com/pub/player/baldemorski/games/2016/05","https://api.chess.com/pub/player/baldemorski/games/2016/06","https://api.chess.com/pub/player/baldemorski/games/2016/07","https://api.chess.com/pub/player/baldemorski/games/2016/08","https://api.chess.com/pub/player/baldemorski/games/2016/09","https://api.chess.com/pub/player/baldemorski/games/2016/10","https://api.chess.com/pub/player/baldemorski/games/2016/11","https://api.chess.com/pub/player/baldemorski/games/2016/12","https://api.chess.com/pub/player/baldemorski/games/2017/01","https://api.chess.com/pub/player/baldemorski/games/2017/02","https://api.chess.com/pub/player/baldemorski/games/2017/03","https://api.chess.com/pub/player/baldemorski/games/2017/04","https://api.chess.com/pub/player/baldemorski/games/2017/05","https://api.chess.com/pub/player/baldemorski/games/2017/06","https://api.chess.com/pub/player/baldemorski/games/2017/07","https://api.chess.com/pub/player/baldemorski/games/2017/08","https://api.chess.com/pub/player/baldemorski/games/2017/09","https://api.chess.com/pub/player/baldemorski/games/2017/10","https://api.chess.com/pub/player/baldemorski/games/2017/11","https://api.chess.com/pub/player/baldemorski/games/2017/12","https://api.chess.com/pub/player/baldemorski/games/2018/01","https://api.chess.com/pub/player/baldemorski/games/2018/02"]}
https://api.chess.com/pub/player/baldemorski/games/2012/08
{"message":"Entity of type 'Chess\\WebBundle\\Entity\\LiveTournament' for IDs tournamentId(150740) was not found","code":0}
My code received and reported a 404 error, inconsistent as it looks up the archives first and doesn't probe. I'm tempted to start with the current month and probe back, but the cross-check with what is supposed to be present and what is is probably useful. A missing arhive vs. a month a player didn't play a game can't be distinguished otherwise. This way they can be distinguished but I still can't get the games.