If you get the error "Accessory Not Found, make sure your accessory is powered on any nearby, then try again", some tips below may help you:

Note: please set up the HomeKit accessory within 15 minutes since you restart/reset it.

a. Reboot Your iPhone/iPad to clear the Home app’s cache, and make sure your iPhone/iPad is on a 2.4GHz Wi-Fi.

b. Follow the user manual to reset the accessory.

c. Power cycle the accessory. For the light switch, please reboot it at the circuit breaker.

d. Configure the accessory again.