Can't connect "simple" push-in Faucet connection

I am humbled to have to post this but I'm ready to break many things. I'm installing a new Kohler Simplice K-596 pull down kitchen faucet and I can not fully make the connection from the end of the faucet hose to the faucet. It's a push-in connection with a plastic collet but I can only get the end 3/4 of the way in, causing water to leak. Am I missing something? I've tried pushing the collet in, holding it out, jabbing the end, slowly working it in, etc but nothing is working. Any suggestions would be greatly appreciated. I've attached the parts diagram for reference.

So, I bit the bullet & removed the faucet, took out the collet & found the rubber o-ring was broken. Luckily, I had an identical one to replace it. Much easier working on the counter than contorted in a cabinet.

I'm glad you found the problem and it was fixable.
Seeing the picture you posted, it looked simple, so it makes sense it was a bad part. Not installation error.