CD Transport signal drop out via different DACS

I have this problem that I can't get a handle on. I own a McIntosh Labs MS300 music server. I use the digital output to drive a Theta DS Pro Gen II DAC and the sound is pretty good. However, when I connect the music server's digital output, to my Theta DS Pro Gen VA DAC the signal routinely drops out and comes back. (there is no optical input to either DAC, for your information). Just for the record, My Pioneer Elite DV09 and all my other CD/DVD players (several) digital outputs into the DS Pro Gen VA work fine and they also work fine going to the DS Pro Gen II DAC also. So, everything works going into both DACS except the McIntosh Labs music server which drops out and comes back when plugged into the DS Pro Gen VA DAC. What is going on here? I spoke with McIntosh and they can't provide an answer and all I get from Theta is silence. any help or ideas would be greatly appreciated. Also, before the sound drops out, it is much better out of the DS Pro Gen VA from the McIntosh server than from the DS Pro Gen II. So, you see why I would like to get this to work.

Thanks, and enjoy