When the phone's Bluetooth and the Zepp app are both turned on, data synchronization will start automatically. Alternatively, swipe down on the homepage of the Zepp app to manually sync data.
If the connection fails, try the following methods: First, swipe down on the Zepp app home screen to manually sync data. If it does not work, force close the Zepp app and then reopen it.
Note: When the watch is recording workout activities or playing music, the app will not be able to sync data to it.