My Bluetooth watch does not measure distance travelled (pedometer doesn't work)
Make sure this feature (pedometer) is declared by the manufacturer namely for that model.
The measurement may be impeded by a protective film on the sensor. Make sure there is no protective film on the sensor, and if there is, carefully remove it. Do not use sharp metal objects for this: as it may damage the sensor.
Keep the sensor clean at all times. Grease and dirt on its surface can significantly distort its operation and sensor readings.
Verify whether the device is tightly put on the hand. Go to the pedometer section. Make swinging movements with your hand, as when walking, several times. The step values should change on the device screen.