[Help] EDO Plugin USB output not working with my DAC

Just trying to get my Squeezebox Touch via USB to the ADI-2 DAC.
EDO is installed on the Squeezebox, so something should come out at the USB output.
When I plug the USB cable into the ADI-2 DAC the following is Shows
USB Sync. conn, SR 44.1, State 2/2 and there is nothing at bit.
If I switch to USB as source it appears SR 768 and internal clock.
So a correct USB connection seems to be established, but there is nothing to hear, though.

I use the USB cable supplied by RME.
Server is LMS 7.9.2

Here's the test I've taken.
I swapped the touch for a second touch. But same result
Another USB DAC was used -> but same result
RME connected to a notebook, RME driver installed, squeezeplay started -> this works -> ADI-2 DAC works in principle.

Does anybody have any idea what else I could test? Why don't they get along?
It's not super important, the touch works great with S/PDIF, but if something does not works, this bugs me.

Thanks for any help. Much appreciated!