As well as Ian's sagacious advice it's worth checking which Comms port the Legacy programme is searching for the 568 on. It needs to match the setting for whatever the device manager has the serial cable on (1-4).

Sooloos, Roon, G series (with LPS upgrade), 800 series (with LPS upgrade), HD621, AC200, Prime and PS, DSPs old and new.

Purdeys, Moke, Leica, 'Blad. Only the best.