This is almost always a driver issue. Ensure you are using the FTDI driver provided with your cable.
Proceed at your own risk if using third-party tools. Yamaha Diagnostic Tool Download Windows 10
Yamaha does not offer a free, public consumer download for their dealer-level YDS software. Most downloads online are either leaked OEM versions, third-party clones, or open-source alternatives. This article guides you through your legitimate options. This is almost always a driver issue