Logitech C922 doesn't work on Epiphan Webcaster X2

I plugged a new Logitech C922 into the input side of my Webcaster X2, which I purchased in February 2020, hoping that the combination would radically downsize my live-streaming kit for portability. I enabled USB video in the preferences, but never got a signal of any kind. The tally lights on the webcam (which works fine on various computers) light up when I plug it into the X2, but no image.
I looked to make sure there were no firmware updates for my unit.
I hate to give up after all the expense of locating and buying a Logitech webcam, which have been sold out for months. Any suggestions?

I managed to get the Logitech C922 working by connecting it while an HDMI camera was plugged in. I enabled USB camera source. Then made sure that “multi camera” was enabled, then chose a side-by-side display with both cameras running. Then I unplugged the HDMI camera and the webcam continued to work by itself, even after restarting several times. Seems clumsy, but it worked.