Ok, all those nodes with the Discover button are dead/ghost nodes. Sometimes when you build up a pile of those it can prohibit devices from pairing.
Here is a guide on how to remove them, try and get rid of as many as you can using the hub removal process. How To Remove Ghosts using hub tools or a UZB Stick
Any time you have a failed pairing it is good to stop, check the details page and see if a ghost was created.
