I have a 4220 kit with one side connected to my router downstairs and the extender upstairs. The wifi works fine from the adapter upstairs using my Mac. However, attempting to connect my PS4 disconnects the PowerLine and causes only the top light to be lit. If I disconnect the Playstation from the network everything is fine again, and the second I try to connect it, using either WiFi or Ethernet cable, it disconnects.
I have no idea what the issue could be
EDIT: Some additional information I just realised - running a speed test also disconnects the PowerLine adapter. If I go to speedtest.net and run a test it the 4th light will turn off and the internet connection will be lost. It will come back on after a minute