c6
Bd7
Nbc6
Nec6
Nd7
Qd7
All of these moves block the check.
The computer says that this is not a checkmate:
White's bishop at b5 is checkmating black's king. Why doesn't the computer recognize this?
The bishop at b5 is indeed giving check to the Black king, and yes, the king himself cannot move out of check.
However, if there is some way in which the check can be blocked, then the position is not a checkmate. Imagine throwing a basketball into the hoop. Yes, the ball travels the correct trajectory into the hoop, but are you certain that the ball will enter the hoop? What if someone intercepts the ball?
Here for example, pushing the c7 pawn to c6 would mean that the White bishop is now attacking the c6 pawn instead of the e8 king, since the bishop cannot jump over an occupied square. This move, therefore, blocks the check and the king is no longer under check.
There are, in general, three ways to evade checkmate.
1. Move the king.
2. Block the check by interposing the path of the opponent's piece (does not apply to checks given by pawns and knights)
3. Capture the checking piece
If none of this resolves the issue, there you have it, a checkmate.
chess.com has some downfalls. I admit. Recognizing checkmates is NOT one of them. If you didn't win by checkmate, then there's obviously at least one more move for your opponent. In this case, it was many. Sorry.
The computer says that this is not a checkmate:
White's bishop at b5 is checkmating black's king. Why doesn't the computer recognize this?