Audirvana for Windows selects UPnP network device but won't play tracks

I’ve been using Audirvana on Mac for yearswithout any problems , streaming to a Naim SuperUniti via an ethernet cable.

However, I’ve just switched to Windows and am unable to stream to the Naim. A+ allows me to select the SuperUniti as a newtwork device, but when I try to play a track the ‘initializing audio device’ displays, the buffer loads but then nothing happens. The playback timer just sits at 00.00, though the ‘stop’ button is highlighted as if the track was playing.

I’ve tried JRiver Media Centre on the PC and streaming to the SU via UPnP works fine.

Can anybody help?