Here's some instructions for backup and reset.
From a Home screen on your companion phone tap the Galaxy Wearable app
-From the Home tab, tap Account and backup.
If prompted, sign in to your Samsung account.
-Tap Back up and restore.
-Tap Back up data.
-Select (check) the desired options (e.g., Phone, Messages, Settings, etc.) then tap Back up.
Samsung Galaxy Watch Active2 - Factory Data Reset (Powered On)
-From the watch screen, press the Home button to open the apps screen.
-Double-tap the Settings icon .
Tap the Checkmark icon. to confirm. If applicable, set up your device.
Galaxy S21 Ultra 512g(VZW), Galaxy Book (original, VZW), Tab S4, Galaxy Watch3 (VZW)
If those steps do not work then you will need to be set up for service. You have the option to call in at 1-800-Samsung or you can send me a private message using this link here (http://bit.ly/2HP0oRi) If you use the link provide the following information.
- Model number
- Serial number