Might be something of use in this article. It mentions disabling browser extensions; the other day another poster discovered his ad blocker was causing problems. Or it might just be the greatly increased web traffic or even chess.com's occasionally overwhelmed servers. Good luck!
https://support.chess.com/article/213-how-do-i-fix-my-disconnect-lag-issues
Every day between noon and 3 pm (EST) if I start a live chess game I keep disconnecting and reconnecting and invariably end up losing the game on time. The weird part is that it is only when I am in live chess. If I'm not in chess.com everything else (e.g. youtube.com) the internet connection is just fine but as soon as I connect to live chess all other apps (and my internet in general) slow down as well. Has anyone had this problem? If so, were you able to fix it and how?