Yamaha DGX 660 keeps dropping

I'm on Windows 10 Pro with a Yamaha DGX-660. I'm using the Yamaha for note entry on a piece, but it keeps dropping out of my I/O settings.

I've tried exiting Musescore before and after turning off the Yamaha, but no joy... I've got it working before, but have hit a roadblock.

Any help is appreciated.