B&W Companion slider stuck installing

I had that problem once when I first bought mine. This is what I done to fix it forever. They are binding up when the post goes into your socket, the powder coat is just to thick to allow it to drop in. I sanded the hitch post that goes intro the socket with a DA and some 600 paper. After sanding off the powder coat, spray the post with slip plate (graphite spray paint) it will drop in easy and allow you to remove it as well.