Trailer Coupling Lever

I've noticed over the past few months that when connecting the trailer to the boat, the lever on the coupler is getting progressively harder to push down to secure it. It is very easy to lift the lever when disconnecting the trailer, and when the trailer is disconnected, the lever moves freely. The coupler also slides over the ball very easily when connecting to the vehicle. I've tried pulling the trailer slightly forward with the truck in the drive to get the ball seated farther forward inside the coupler which doesn't seem to help. since it clearly states "do not force closed", is there a spot that I should be addressing to make it latch better?