Powerline adapters paired, all lights green, but not visible on devices
I purchased WPA4220T starter kit, in Oct 2019. All paired, worked fine for quite a while. Then one of the powerline adapters stopped being visible for both laptop and phones. So factory reset, paired again, all lights were on, on all 3 units, but still not visible. So we thought it was broken. So we bought an add on powerline WPA4220 2 port range extender. Paired it, all lights are on, but even this new one is not visible. Downloaded the TP Utility software, plugged in adapter, it finds them all, all lights are on, they are talking to one another. Can someone explain why we cannot see one of the adapters. Thanks in advance.
Also, the one that is working, does seem to cut out a lot, and we are always switching it on and off.