Unresponsive Device

Hi, i have bought 5 LED Bulb 1s (color) an like in topics below device could not be added thru YEELIGHT app. However i was able to add it on YEELIGHT app Via Homekit QR. I am using Alexa, my problem is every time someone accidentally turnd off the light switch or every after blackout, when power is back it becomes unresponsive.