Lost on time while my opponent ran out of time

I just played a rapid game of 15 minutes.
After loosing a piece my opponent did not move anymore.

I have 13 minutes and 32 seconds left on my clock.
The clock of my opponent is red and stands on zero.
After the game Lichess did not say who had won the game.
When I checked my results I see I lost the game on time.

Very strange.

seems like an internet issue , you probably lost connection to the server

It happens more lately. Your last move probably did not reach the server, so you ran out of time.
It is a server problem. The server probably gets overloaded by too many players.

There was a server restart: github.com/ornicar/lila/issues/6695
I'll donate to lichess to make sure this will happen less often in the future. Let's support the servers better :)

Two times I got the message "Your opponent left the game, after x seconds you can claim the game", so it looks HE did lost connection. Its very strange, for it happened just after he lost a piece.

It looks like a bug for Ichess did not say who had won the game.
The clocks also indicate that he has lost the game.