Is this really mate?
[Event "Live Chess"] [Site "Chess.com"] [Date "2025.11.19"] [Round "?"] [White "4iAtlas"] [Black "sherzod131090"] [Result "1-0"] [ECO "B01"] [WhiteElo "647"] [BlackElo "606"] [TimeControl "600"] [EndTime "19:31:48 PST"] [Termination "4iAtlas won by checkmate"] [Link "https://www.chess.com/analysis/collection/20112025-2ZyKoMyqG/2Zpec8BTfk/analysis"] 1. e4 d5 2. exd5 Qxd5 3. Qf3 Qxf3 4. Nxf3 e6 5. Nc3 Bb4 6. Nb5 Kd7 7. c3 Bc5 8. Ne5+ Kd8 9. Nxf7+ Kd7 10. Nxh8 Nf6 11. Nf7 Kc6 12. a4 a6 13. Ne5+ Kd5 14. d4 Be7 15. Nxc7+ Ke4 16. Nxa8 Bd6 17. f3+ Kd5 18. Bc4# 1-0
This says puzzle solved, but it seems like just check to me, not mate. Black's queen could move b8, no?
Puzzles often stop after the correct move or two. The puzzle you played on dec 2nd if you go back and look - black just castled and there are only 3 vacant squares next to it. Two of those squares are controlled by the Knight d7 and b7. 1.Qxa6+ Now the King must move to b8 Kb8. 2b7 Now the Queen can move to b7 because it is protected by the knight 2.Qb7#
A little tip- whether you win or fail a puzzle and you are not sure or don't understand something click on the green/red button so it shows again, and then click on the magnifying symbol which takes you to analysis. There you can read the lines, make moves that you think may work etc etc.
Edited to add - Just noticed you said Black queen to b8 (Qb8) apparently, I was looking at the wrong puzzled - provide the date and puzzle number or a link for help.
This says puzzle solved, but it seems like just check to me, not mate. Black's queen could move b8, no?