Chess server did not accept my last legal move!

After I tried playing 20...Rd1+ in the following game: lichess.org/VX1hHePFAyt9 the server kept running my clock down to zero. The server accepted my move only after I had run out of time! This is definitely a bug that needs to be fixed!

It could be because of your connection. It happens to me all the time.

Maybe refreshing and reloading the page during the game would have worked.

I do have the same experience. That happens to me, when I have bad connection. Lik3 finlip.