I worked with Google support today and we removed and added back in the nest protect and it still shows as offline. The Nest thermostat is a Gen 3 and it shows the family room, but the master bedroom shows as offline. The google representative told me that the generation 2 nest protect doesn't have a temperature sensor, but it has since I purchased it almost 3 years ago. When I test the Nest Protect it is successful. The representative told me to call back once I found the temperature sensor in my master bedroom, but the Next Protect is all I have ever had in my bedroom.