After using several lamp controls and a 823LM wall switch successfully I decided to purchase another wall switch. After wiring it up it works with the physical switch and the garage door opener. When I try to add it to the app, the lights controlled by the switch blink once and the garage door opener lights blink once but the learn light on the switch blinks 20 times rapidly and the app says no device added. I thought that I might have mixed up the load and the light so I reversed the connections and had the same results. It is connected to a good ground. Does anyone have any ideas or should I just exchange the unit for a new one?