Computer to Symphony Desktop to KEF LS50 Wireless II via Optical

I connected symphony desktop to my computer via USB then used a toslink/toslink optical cable to connect symphony desktop to the LS50 Wireless II (also set to optical source). But never got a sound - did I do something silly? Thanks in advance!

I may be misunderstanding your setup but did you set the output of your PC to optical?

Does it show up as an output?

thank you for the reply - the mac is set to output to symphony desktop via USB. when I plug in my headphones to symphony desktop the computer sound outputs just fine. But when I connect KEF LS50 Wireless II via optical to symphony desktop there is no sound

The only thing I can think of is that the signal being output from the Symphony is not in S/PDIF, but then I’m not particularly familiar with the Symphony. From what I gather, there are three optical I/O formats - S/PDIF, SMUX and ADAT.