Check in the app

Sensors which are currently connected and communicating with the app show a small Bluetooth icon on the My Butlers Page when in range. If your sensor does not show connected or has not connected try restarting the app or toggling Bluetooth. If sensor still shows not connected and no data appears on the History page, refer to What do I do when my sensor won’t connect?

Check if the battery is dead (Red LED blinks)

When a charged 3v CR2032 battery is removed and reinserted into the battery holder, an LED light blinks 4 times on the top of the sensor. The absence of 4 LED light blinks indicates that either the sensor battery is dead or the sensor is not functioning properly.