Why this is not a checkmate?

Hye, can someone explain to me why this move is not a checkmate?  Or it is just a computer error?

This is a unique move in chess called en passant , white pawn on f5 can take black pawn on E5

Yes, this forces en passant, with check. You will end up losing a rook.

More specifically, the white pawn moves to e6 which removes the black e5 pawn. It's the only type of capture where you don't land on the same square as the captured piece.

This weird type of pawn capture can only be done immediately after the victim pawn moves 2 squares. If you wait for another turn, the en passant capture is no longer available.

thanks, now i understand

This is very rare

Your opponent can en passant with check and you will lose your rook

This is the game: https://www.chess.com/game/live/69168983789

White resigned!??  Why? White also thought it was checkmate?