@JeanValjean 

The solid amber would indicate it is booting up, after being restarted, which should then blink green indicating connecting to the Wi-Fi. However, if there is an HS210 installed on the other then, try pressing and holding the main button for five seconds. The LED light should blink then eventually turn off.

@JeanValjean did you ever fix this issue? I appear to be having a similar issue where one end of my hs210 circuit will not connect to wifi (or work to manually turn the lights on/off, except when I hold in the reset button). It's in a 2-gang configuration next to a 4-pole switch, with an enerlites cover, so I was wondering if any of that would affect it (I have similar configurations elsewhere that work just fine).

@loolaide 

If you are setting up two HS210s on one three-way circuit, only one needs to be connected to the WiFi, the other does not. If you press and hold the main button, after five seconds the WiFi light should change then turn off.