Suddenly my powerline adapter won't connect to the other one. They connect fine if they are in the same room, but if I move the other one upstairs it doesn't work. They have been working fine before s

Is it possible to buy a non kit version of the TL-WPA8630 KIT? I would like another adapter to connect in a different place in the house, so that I have 1 connected to the router, and 2 elsewhere in t