I just had a look at the game and it is because YOU didn't have mating material left. It doesn''t matter how much material the person that runs out of time has, it matter how much the other person has. Because you were the one that still has time left, but didn't have mating material, it was a draw. Hope this helps :)
I won on time ,why is it draw?
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It says clearly: Insufficient Material.
Please see my most recent game , i had a king and knight(which would have been captured if my opponent had enough time) and my opponent had a rook,knight and three pawns which is more than enough to beat me as i was left with a king alone.
It is a draw because YOU did not have sufficient material to mate him.
Chess.com uses a simpler system, if you have just a king and a knight or a bishop it will be draw if your opponent rans out of time.
If it was USCF rated it would also be a draw, if it was FIDE rated you would have won because it is possible to mate him with a knight as long as he has other pieces as well.
If YOUR OPPONENT runs out of time YOU need to have sufficient material to mate him.
If YOU run out of time YOUR OPPONENT needs to have sufficient material to mate you.
I won a blitz game on time but the result was a draw!!(my game against 'Stari_Gavro') ,my opponent had enough material to beat me ,but he/she lost on time why is it a draw?