Your device's firmware isn't up to date.
Tap the sync button to receive a firmware update notification.
After updating the firmware, please attempt syncing again.
When the LED on your MOTHER device alternates between white and red blinking, it indicates that a firmware update is in progress.
If you don't observe the LED blinking, it's possible that your app isn't up to date.
Update your app to the latest version before proceeding with the firmware update.