Here are the steps that most often resolve the issue:
1. Make sure the audio cable is fully plugged into the iPad and the iPad volume at the maximum.
2. Make sure the latest version of iOS and Zoom App is installed.
3. Check that the color frequencies are properly set in the ZOOM dashboard. If you're not sure what this looks like, you can see a screenshot of the ZOOM menu here:
Green (available): 1500 Hz
Red (occupied): 370 Hz
4. Restart the iPad
5. From the iPad play this test video:
If the light color match the color of the screen then the enclosure is fine and your problem is on the ZOOM side.
If the issue persists you can open a Tech Support Ticket or send an email to firstname.lastname@example.org