This Smart socket has been used daily for a long time but recently, I think today, stopped turning off automatically. 
 

On the app, turning off and on are acknowledged but the louder click is only heard when turning on. Pressing it's button also doesn't turn off connected equipment. 
 

i have this equipment connected to it: 1) an air purifier (75W) & 2) Apple charger (20W). Sometimes also a subwoofer (19W), but that's infrequently active. 
 

What can be done? What's the warranty?