draw/stalemate
I had this happen to me a lot too.
"Stalemate is a kind of draw that happens when one side has NO legal moves to make. If the king is NOT in check, but no piece can be moved "
So even if you have a lot more pieces and appear to be winning, it can end in a draw stalemate because your opponent has no legal moves to make.
This tends to happen a lot if you promote too many pawns to queens, instead you should try a rook or castle
Here is a good example of a stalemate. Even though white seems to be winning by a lot, its a draw by stalemate because black cannot make any legal moves, and is also not in check
At least on your account at the time of writing, you have zero games played. Only three puzzles attempted and that's about how far your games record goes.