Hi Steve, thanks so much for the quick reply and advice.
I contacted ESI and they gave me a quick reply which solved the problem. It turns out that there are inputs on the back of the device, not just the front, and a button to choose which inputs are active. https://kb.esi-audio.com/?goto=KB00273EN
It did not occur to me that there would be inputs on the back, and as soon as I changed it to use the front inputs it started working.
So, that was a real easy fix, and a bit embarrassing, but I guess I’m not the first person to run into that since there is a knowledge base article about it.