McIntosh MS 300 server and Theta Compatibility

I run the digital coax output of my McIntosh Labs MS 300 Music Server into a Theta DS Pro Gen II DAC and it operates very well. I recently purchased a Theta DS Pro Gen V DAC which I run the digital coax output from My very good Pioneer Elite DV 09 transport and it also works very very well. I tried to connect the McIntosh MS 300 coax digital output to my Theta DS Pro Gen V DAC and the sound stops or skips all time time on all music. Both DACs work great when connected to their specific transports. What is going on here? Is there some sort of software issue with the McIntosh MS 300 such that it has problems with the Theta DS Pro Gen V? or the other way around. I have used many different cables and the same thing occurs. Also, the MS 300 only has coax and optical digital outputs and the DS Pro Gen V does not accept optical input.