What's the model number? Did you upgrade the latest firmware? What's the firmware version? How about status of all lights on the range extender after you finish configuration? To solve it more...

If the range extender is out of range of the main router, you cannot configure it as a range extender anymore. There are two powerline adapters, right? You may try access point mode. Main...

Did you try to configure bandwidth control to see if it helps? Also you can downgrade the first firmware to see if the problem disappears? If there is any advice from Sony, update it here...

Upload speed is slow ot it doesn't upload at all? Try different ethernet cable to connect them or test upload wired using a different PC.

Did you install powerline utility of PA4020P as below on your PC? http://www.tp-link.com/en/download/TL-PA4020PKIT_V1.html#Firmware Under Advanced Tab, select Online Gaming for a try. Check the rate...

No powerline utiity for Linux... To login its web interface, there is another method. Manually configure a static IP address for your connection, wired or wireless. The IP address should be...