why when I win by time. the system says "draw by insufficient material"?

Does anyone know?

In order to win on time, you must have sufficient material to create a checkmate, otherwise you only earn a draw (the best result you could get with the material you have).

I once experience such. I have sufficient material a queen and a bishop. But my opponent just a king.I should win by time, but the system said draw by insufficient material

Kindly check through my completed game recent example is a game against harryterms. I have sufficient material but I was surprised the system said draw by insufficient material.

TunjiGold - in that game, white (your opponent) was the last to make a move.  Therefore, you were the one to run out of time.  Since your opponent didn't have sufficient material, the result was a draw.