Solution:
1. Please check whether the APP version of the mobile phone and the firmware version of the watch are the latest. If they are not the latest, try to upgrade first.
2. Please check the network connection of the mobile phone. If the phone Wi-Fi connection is disconnected, please try to reconnect; if the Wi-Fi connection is normal, but still cannot sync, please use the data.
3. Check the connection status between the watch and the mobile phone, make sure that the Bluetooth is connected normally, and try to refresh the APP several times.
4. You can restart the mobile phone Bluetooth, restart the mobile phone watch to try.
Does it help?