If you have security setup on watch, you might want to unlock it after putting it on your wrist. I would also check the snore section in the health app on the phone if the snore option is on. If it's on, check the Detection snoring options, Always or Once.
1. No security setup
2. Snore detection on, have tried both always and once.
3. Worked when I first got the watch, stopped working after the 8/25/2021 update. Many other people have complained it is not working.
Maybe you stop snoring. For reference, my Watch software version is R890XXU1BUI5. My wearable is version 220.127.116.1183061. The health app is version 6.18.8.005. I have no issue with recording snore. I know I'm snoring during sleep. I have all health monitors set for continuous.
Watch doesn't detect snoring. Smartphone does. Watch just detects when you start to sleep and notifies smartphone to open the microphone and listen. And smartphone will do this if conneched to the charger only since continuous recording drains battery.