How is this situation not a checkmate? According to the chess app I am using, this is not a checkmate against black:

[FEN "1rk4r/1p6/3p3q/Q1pPbRnP/p1P3B1/P6P/1P4R1/7K w - - 0 1"]

1. Rf7+


How is it not? I think the black king is checkmated by the queen and the white-squared bishop.
It is not checkmate because Black can interpose a piece to block the check from the bishop: move knight or queen to e6.

It's still only a miniscule delay for the inevitable.

[FEN "1rk4r/1p6/3p3q/Q1pPbRnP/p1P3B1/P6P/1P4R1/7K w - - 0 1"]

1.Rf7+ Ne6
(1...Qe6 2.Qc7#)
2.Qc7# 1-0