@nicholasj 

Hello,

Did you mean that when you add the TL-WPA 4220 to the network, both 9020 adapters stop working? And you can only see the wifi network of TL-WPA4220?

Since TL-PA9020P KIT does not have wifi function, so after you pair them, you can see the default TPLINK network name, and you can find the wifi password at the bottom label of the TL-WPA4220. Then check if you can get the Internet from the TL-WPA4220.

You can refer to this link to add the TL-WPA4220 again:

https://www.tp-link.com/en/support/faq/319/

You can try to put all powerline units and your router in the same room, then check if they can work well.

If it still not working, please tell me the LED light status on the 3 units. May I have a photo of them?

Hope it can work and have a nice day!