I am using this app with Imou Bullet 2. Something wrong with the alarm sound feature when you set up the smart scene. If you disable the "alarm linkage", but enable "sound the alarm" feature in smart scene, it will not generate the alarm sound. So you need to enable "alarm linkage" feature, but then it will sound the alarm even you have removed "sound the alarm" feature in your smart scene. PLEASE LOOK INTO THIS.