1. Confirm your Apple Watch is connected to your iPhone. Swipe on up your watch — a green symbol of your iPhone should be present in the top left corner. If not, ensure your Apple Watch is within range of your iPhone and turn off and turn on both of your devices.
2. Once confirmed connected, open Sleep Pulse 3 on your iPhone. Then, go to the settings page on your Apple Watch by swiping right from the main page in the Sleep Pulse app on your Apple Watch. Scroll down and tap, "Sync Again": Sleep Pulse will re-analyze the data and attempt to re-sync with the iPhone app.
3. If problems persist, restart both devices and repeat steps one and two.