I bought and installed a dozen Kasa HS200 Smart switches for my home. Three of them have connected and the rest will not connect at all. I have tried everything I can think of. I've reset my router, unplugged two of the three Eero hubs so there's only one on at a time, I've reset and restarted each switch multiple times, turned the breakers on and off, and rebooted my phone.  I've even gone into the network settings to only allow 2.4GHz connections, then ensured my phone is connected on that frequency before trying again.

I keep having the same issue: the app will recognize the switch and ask me to connect, I click it and it thinks for a minute then gives an error message of "Unable to Connect to Your Smart Switch Wi-Fi." Nothing seems to change the outcome.

Routers are 3x Eero 6 Pros. Modem is a Motorola Surfboard.