Sleep app has stopped tracking
Sleep tracked up until December but hasn’t tracked since
Apple Watch Series 6, watchOS 9
Question marked as
Go into your sleep schedule in the Health app on your phone.
Delete the existing schedule and create a new one exactly the same.
I'll bet that it'll start working again.
Another thing that you can check...
In the Watch app on your phone, go into Sleep and make sure that the "Track Sleep with Apple Watch" toggle is green.
Track your sleep on Apple Watch and use Sleep on iPhone - Apple Support
Let us know if you need more help.