I’ve just had a similar experience. Got an Innuos Zen on Friday to replace an AURALiC Aries and my PC Roon server. After getting everything hooked up (CAT 6 Ethernet from router to Zen, Curious USB cable from Zen to DS senior), it looked like the Zen was delivering a good signal to the DS DAC (the display on the DS looked right, green light, the right info about the sample rate, etc.) but no sound was emerging from my speakers. I messed around with various settings on the Zen for quite a while (since it was the new thing) until it occurred to me to reboot the DS DAC. That did the trick, and everything was good until I changed the Zen from standard Roon server mode to the ‘experimental’ Roon plus squeezelite mode. Once again everything looked good, but no sound. A reboot again solved the problem. Since then I’ve had to reboot the DS several times, whenever something interrupts the stream from the Zen. One time it was me changing the Ethernet cable that fed the Zen, which didn’t seem to bother the Zen, but muted the DS. Other times it was just some glitch in the Roon plus squeezelite mode that caused the Zen to stop playing, and then the DS would be silent when the Zen started playing again. So far a quick reboot of the DS has always fixed it. But it’s nothing that ever happened during all the years I was using the Aries. Even though the Aries would often freeze up for one reason or another, and I often hot-swapped cables and such, the DS never exhibited this behavior and never needed a reboot. Puzzling, though not really a serious problem.