That means the device has not been communicating with the hub for a while. This is normal in most cases, if you don’t use a device for a few hours it can show as inactive. Just change some settings to force it to communicate with the hub and it’ll show as active. If you can’t change the settings with thermostat then your hub may have lost communication with the thermostat. In such a case hit the reset button the thermostat or you may have to exclude and re pair your thermostat depending up on the condition of your hub/thermostat pairing.
