I got a cat door installed on the door that leads from my kitchen to the garage. I keep the litter boxes and food in the garage and been trying to train the cats to go through the cat door. As of now they will only go through if I have the flapped rigged to be held open by bungee chords. They won’t go through with the flap down. I think the problem is that the flap is a hard plastic that seals so bugs and hot air doesn’t come into the house, so instead of a normal flimsy plastic type flap, this one has to be pushed on a little harder to open for them. I could always get another kind of cat door that might be easier but I like that this one is keeping bugs and weather out. Is there any tricks to get them to start using the door with the flap down? I tried just keeping them in the garage with the flap down so they would have to use it but then they don’t and they just stay in the garage and I feel bad. Any tips would be appreciated, thanks!