Chess Online

I also did this.
But after analyzing, white is winning after Qd3+.
The king goes to f2 and can - if needed - escape to g3. More importantly, the white rooks link up, and can protect against the advancing pawn.
Moving Qa7 is much better and will win the game. King is stuck at the last row, pawn can advance, and the best response white can do is Nxd6, which is replied to by either
Qa6 - winning the knight or simply moving the pawn forward winning a rook in the end, i think

Ie the third and last move of the exercise.
So everywhere we wrote a7 one should read a2