Receiving Site Cannot Unmute

I am an audio-visual technician at a school district that uses Zoom Rooms with iPad controllers. The teacher at one of the hosting sites notified me that one of her receiving sites is muted, and they are unable to unmute themselves (and she cannot, either). I can manually unmute them by remotely launching their controller, but obviously we don't want to keep having to do this. Under the Participants tab of the host’s iPad, I clicked on the three dots, and one of the options was "disable participants to unmute themselves". This means that self-unmute is allowed for receiving sites, so I'm wondering why only this particular receiving site can't do this. In admin center, I went to the meeting tab of settings, and I can see that Request permission to unmute is enabled. Any other suggestions?