Sleep is measured incorrectly
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.
Canyon smart watch and fitness wristband are not measuring devices. Sleep indicators should be regarded as indicative.
To display sleep, the sensor should fit tightly to the wrist. When you don't move and your heart rate slows down at night, the sensor starts counting sleep. If you move your hand when sleeping or wake up, the sensor will stop counting the sleep.