Started new game. *Could not see my pieces.* Game aborted and I was given message I'd be temporarily banned by not playing the game.
lichess.org/forum/lichess-feedback/i-cant-see-the-piecesAlso, you can update your browser or try a different one.
You won't get a temporary ban for one game. It's just saying, aborting games will lead to a ban if you continue to do it too often.
I guess make sure you don't have blindfold mode on but more likely this is the weird browser bug that randomly causes some pieces to be hidden in rare cases. Usually doing a hard reload (Ctrl+F5 or Ctrl+Shift+R) will solve it.