Does Your Cat Fly?
Cats are pretty indecisive creatures. One moment, they’ll paw on a door as if they want to get out. But the moment you let open the door for them, they’ll stare up at you as if you offended their ancestors. It’s a lot better for your sanity to pick up a kitty door, so your kitty can leave and come back on their own accord.
Just make sure you install it properly. And by properly, we mean don’t do what the OP did. You have to take the door down and saw a portion of it off to install this particular kitty door, but they made one huge mistake. They sawed off a portion from the top of the door.