I have Powerline AV500 2 port passthrough powerline adaptor (TL-PA4020P) and a TL-WAP4220 (powerline + wifi).  I bought them in 2016 in case that helps to identify the version, which I can't find.

It has been working well for a long time.  Today I addded another powerline adaptor my network and it worked fine.  I confess it's a Netgear someone gave me.

But now my initial setup doesn't work.  I've tried resetting the WAP4220,  plugging, unplugging, different durations of pressing the pairing button , etc.  I reset both units - the PL-4020P by holding down the pair button for a long time, and the other using a paperclip in the reset hole.  No matter what I try, i can't get it to work, but ti seems very unlikely to me that just setting up the Netgear adaptor fried my devices.

Anyway, what should I do?  Is there a physical way I can reset the PA4020P?  Anything else to try?  I don't have a windows machine - just osx and linux.