Participant's videos are not showing. Their screens are black. They can see me, but I can't see them

I just purchased a Zoom Pro account. The person I had a meeting with could see and hear me. I could hear them, but their video disappeared and their screen went black (without their user name - just completely black) and they were still sharing their video. My wife and I tried to Zoom each other after my meeting and the same thing happened on my computer. Her screen went black. She could still see me. How do I fix this? I saw other people post the same problem and someone replied saying they were creating a support ticket. Can someone from Zoom please do that for me? Thanks