The steps below apply to the following models:
Restart Apple Watch
Force Apple Watch to Restart
If the Apple Watch won't turn off or if the problem continues, you may need to force the Apple Watch to restart. Do this only if you're unable to restart your Apple Watch.
Hold down the Side button and the Digital Crown at the same time (for at least 10 seconds) until the Apple logo appears.
For additional help, refer to: Apple Watch Support.