@j0np Are both of your Kasa switches connected at the line end in each case? (with the common connected to the live line voltage?) I think this is the easiest/most reliable way to connect these....

@MikeandMary Can you post image of the 'settings' in Alexa for the devices that do not respond? (also compare with the one that does, look for discrepancies) You gave each one a unique name I...

@Jack139 - if you can wait a few months Kasa has announced release of a 3-way dimmer, expected to be available around the summer I believe For what you propose - You will not have true 3-way...

Here's simple test for you: Connect your line (first validate that it is indeed your line and does change with state of any other switches) to the black terminal and the neutral - leave the two...

dmd4home wrote ......I could turn the lights off with the app, but when I tried to turn them back on, the app said: "Device Unreachable, Your device may be powered off or out of network range"....

@dmd4home You only need one HS210 and it should definitely work if you connected it correctly. The HS210 is no different than the 'normal' 3-pole switch that you are replacing - just that it has...