Yep same, this has happened to me multiple times. Supposdedly they are working on it, but no sollution yet. This doesn't happen ever on lichess...
Says 'Reconnecting' even though Internet is fine... lost game
Chess.com is experiencing issues recently with their servers being overloaded with increased activity: https://www.chess.com/blog/CHESScom/chess-is-booming-and-our-servers-are-struggling
Happened to me yesterday - my Internet server was down for about ten minutes. Rare but it happens.
A couple of months ago I was winning a game I was playing in a coffee shop, using its Wi-Fi connection. Which stopped functioning. Oh well...
That about sums it up. Was in a winning position when suddenly the signal bar started saying 'Reconnecting...'
I checked multiple other sites and Internet was working. Even chess.com itself was loading fine on other pages like profile or home page. Only live chess disconnected, and when it came back on after about a minute, I had long since lost on time.