As host, I could not hear participants but they could hear me and each other

I tried to host a meeting this evening in Zoom basic, as i do almost every week.  I tested my microphone and speakers before and a couple of times during the meeting, and they worked fine.  But when participants joined, I could see them, but not hear them.  They could hear me and see me fine, and they could hear and see each other, but I could not hear any of them.

I ended the meeting and restarted it, but it did not change anything.  I still could not hear them, but they could hear me and each other.

Any thoughts on what the problem might be.  IT gave me a new camera, because updating Windows 11 last week killed my old camera's driver, but i don't think it would be that because they could hear and see me.  i just couldn't hear them.