Not a check?

Can you please tell me why this isn't a check? I understand that knight can eventually capture the queen, or black's bishop can just block the path to the king. However, how is this not a check? 

That lesson was looking for checkmate, not just a check.

it's because if you do any other move apart from the one it want's you to do and a few select moves then it'l say that move. and because that move is so terrible the makers didn't expect you to do that move.

Thank you for your responses.

It's funny that the lesson was obviously programmed to say any incorrect move apart from 4.Qxf7++ was not a check, they person that wrote the lesson clearly never anticipated anyone would play Qxe5...

You were on the right lines though malanne - unlucky. 

It is a check but it wants to list for checkmate and 2 the knight can capture,they were looking for the four move checkmate.