K50 usb out to Bricasti M21-no usb choice in player dashboard

I have tried all of the recs in the troubleshooting section. I cannot seem to get a usb output option from the K50 player. The K50 works fine using the digital aes to the Bricasti M21 Dac.

Pardon me in advance if my questions seem very elementary considering you have gone through the Troubleshooting options. Have you confirmed your USB is attached to K50 USB Output and not Ripper or Disk USB connections of the K50? Did you indeed try a different USB cable to the K50 and your DAC. When viewing the Antipodes Player Dashboard, is USB Audio shown as an option for Output.? Is it highlighted and have you selected Save? Have you restarted the K50? Best of luck

Thanks for responding. It has been determined that the MDX board in the Bricasti is bad.