Try my.innuos.com on your iPad browser or a computer. It’s the same thing as the app. The Sense app in my iPad can be a bit clunky and sometimes unresponsive. You will also need to disable Roon first on Innuos settings before being able to use Innuos for streaming music. Just a toggle off/on for Roon under Settings.
Where is your music stored? zenith’s internal SSD? How are you connected to your DAC? Sense will only work when connecting your Zenith via USB to the DAC