For full compatibility with Galaxy Watch 4 and 5 (OneUI 4.5) please update Wear Stand Up Alert to the latest version (v2.31 or newer).

If you are using Bubble Cloud, update it as well to v10.11.3 or newer!

Notifications are not enabled by default on the Galaxy Watch!

Follow these 4 steps to enable (screenshots help below)

1. Watch Settings in the Galaxy Wearable app
2. Notifications
3. More
4. Find Wear Stand-Up Alert in the list and enable its notifications!

More information

Wear Stand Up Alert