Why didn't Stockfish see the check mate threat?

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Kkj9kk
In this game, I needed to move the knight out of the way so my rook could access the file. I was hoping the queen would take the knight, allowing me to move the rook to D8, which would lead to a checkmate. This should have been a brilliant move. no?

justbefair

Stockfish would have seen the checkmate threat but would have also seen that black could win your knight with that queen fork on a1 and still have the time to stop your checkmate threat.