It could be one of the following reasons:
- The watch may be disconnecting if moved outside of the phone’s Bluetooth range. Bluetooth range is 10 meters (30 feet) if there are no doors, walls, or other obstacles between the phone and the watch.
- Bluetooth may be disabled on the phone. The app will notify you that Bluetooth is not on and will ask to turn it on. Try enabling Bluetooth on your phone using the phone’s Bluetooth settings. If it is already enabled, try turning Bluetooth off and on.