I've just played a game in which it was the other players turn and the game simply ended with them winning having not made a move and with lots of time left on both clocks - has this ever happened to anyone else?
Sounds like you got disconnected from the live server process.
https://support.chess.com/article/213-how-do-i-fix-my-disconnect-lag-issues
I've just played a game in which it was the other players turn and the game simply ended with them winning having not made a move and with lots of time left on both clocks - has this ever happened to anyone else?