I bought and installed tp=link smart plugs and a HS200 switch with no issues. I then bought a HS210 set. When I checked I only had a common (White) lead in one of the two boxes, so I just wired one HS210 switch and it works perfectly. (Ijust mad sure after programming the switch I said finished to the other questions in Kasa). When I tried to wire the second switch into a different 3 way switch system in my home, as in the first case, only one box had a common wire so I put the switch in the box with a common wire checking all the connections. When I turned on the breaker the light attached to the switch blinks on and off and the switch clicks. This starts a second after the power to the line is turned on. Any ideas? I've double checked the wiring between the two switches and it seems to be OK.
HS210 switch turning on and quicly off