Dropout with my first Musical Fidelity DAC w Sonos

I am running a wired Sonos music system throughout my house.
The Sonos works great and sounds better than you would think.

I decided to add a Musical Fidelity V3 Dac to one of the Sonos digital outs to my Preamp in. Sounds good but I am experiencing momentary dropouts of sound.

The source is my PC based music server

I am using a Toslink optical cable. I hooked up the DAC and cables to a Sony CD Player and it works perfectly no issues.

My Spidey senses tell me that it is an issue with the PC.

But I am an Analog man at heart and have no technical understanding how to fix this.

Any suggestion would be appreciated, there has never been an issue that this forum has not resolved.

Thank You for your time!
Best,
Bruce