Assuming this complaint is directed toward Chess.com, it's not the fault of the website. If you practice some basic endgames you'll notice that certain pieces cannot help a King deliver checkmate. In that case, under the rules of chess, there is Insufficient Material to bother trying for a checkmate because it is impossible.
Some examples of games that are drawn due to Insufficient Material:
King vs King+Knight
King vs King+Bishop (that is, a Bishop of either light or dark squares)
King+Bishop(s) vs King+Bishop(s) (assuming that neither side has Bishops of both light and dark squares)
King vs King (of course)
King vs King+2 Knights
The last one may come as a surprise to some people who have heard that checkmate can be reached in a King vs King+Bishop+Knight. A quick glance at the material count shows how both cases are equally matched in terms of point count:
King vs King + Bishop(3 points) + Knight(3 points)
King vs KIng + Knight(3 points) + Knight(3 points)
Yes: King vs King+Bishop+Knight can lead to checkmate for the winning side with a complicated procedure. However, though the point count is identical, it is still impossible for a King and 2 Knights to force a checkmate on a lone King.
Hope this helps!
I win on time and the game is drawn by unsuffincing material. Happens all the time. Why don't you fix this?