Check the following points.
System program version
You must update the system program of the piano to the latest version. For how to check the current
version and update to the latest version, see the “Downloads” tab on the Web page of the product in
question.
OS installed on mobile device
The OS used by your mobile device must match the app’s requirements to run. See the following URL.
The location feature on your mobile device must be turned on.
If you’re using an Android device, see the related Q&A, “I can’t connect via Bluetooth after updating to
Android 10.” (For Android 6.0 or later, or iOS)