Zoom Won't Let Me Use USB Microphone Despite Testing Well

I need to record a Zoom meeting for an educational video, and I'm required to use an external mic for a better quality of sound. I have a fine and working USB microphone, which Zoom does seem to recognize as a speaking option.

However, whenever I try to choose this option, an audio test prompt jumps up, I test both audio and the microphone, all seems to be working fine, but then Zoom asks me again which option I want to use, I choose the USB mic again and am again directed to the test box, ad infinitum. 

Am I doing something wrong?