There were no other options to try, but I figured it out. I noticed that the card was visible in Dante Controller only when I was connected to WiFi, and not via Ethernet. Turns out I had to go to the ‘Configure Dante Interfaces in Unmanaged Mode’ preference page in Dante Controller and change the Primary Interface’s network from en1 to en0, and then DanteFirmwareUpdateManager found the device and updated it.
