@Brook Hi. Yes, I've tried to hold the button for more then 10s. Also the main button, and both. But as there is "no sign of life", that is no light in main buttin, I believe there is a main fault....

Got 10 HS110/100, working fine. However, today one of the HS 110 was no longer connected to the app. It is no longer turning on, that is, no light in the on/off switch, Tried several other outlets,...