Common causes and solutions:
1. The underwear band has flipped on your waist
Ensure that the garment band is sitting flat on your body throughout the day.
2. Your skin may be dry
Moisture improves skin readability. Apply moisturizer where your skin is in contact with the garment band.
3. You're moving too much
Rigorous movement may affect the signal. Try taking a break and see if the connection is restored.
4. Disabled location settings on Android
If you have an Android phone, ensure that you have enabled all location permissions.