It means you are losing your connection. There is a Help topic with suggestions you can try.
https://support.chess.com/article/4560-it-says-game-abandoned-but-i-still-had-time-on-my-clock-whats-going-on
If you need help, please contact our Help and Support team.
This is playing on my iPhone.
Chess.com, please fix your app! This happened 3-4 times to me just tonight, very frustrating!