Mackie Onyx12 Mic Issue

Hi,

I have a Mackie Onyx12 mixer.  I can get sound out in my Zoom meeting by choosing Onyx12 1-2.  However, whenever I choose Line (Onyx12) in the Microphone drop-down, I get an error "There seems to be an issue with your microphone, please select a different device and try again."

I have my mic connected in channel 1.  I know it works because I could hear it directly in my main speakers.  It is just that I'm having this difficulty connecting it to Zoom.

Appreciate help on how to make my mic work.

Thanks,

Mike