What does this message mean that I get after every game that I play ? "This game does not qualify for player league"
It is about the Players League where you can earn points and compete with others to get promoted to new level divisions. It's purely for-fun and does not have any impact on your chess rating.
Not all games can give you points for Players League. So that message is popping up to tell you.
More about Players League: https://support.chess.com/article/2813-what-are-leagues-how-do-i-join-one
What does this message mean that I get after every game that I play ? "This game does not qualify for player league"