Unable to record using FaceTime HD Camera in iMovie for Mac

I'm trying to record a video using the built-in camera on my MacBook Air, but when I do, I receive an error message. In iMovie, I click on the arrow pointing down where it says "Import Media", I select "FaceTime HD Camera", I select the event I want to import to, and then I hit the record button.

It says "Recording..." for a few seconds and the green light appears indicating my camera is on. After a few seconds it automatically stops and gives me the following error message: "Import was aborted due to the lack of incoming data from device. Check your connections and that the deck is playing."

I checked my system preferences and I do see that I have allowed iMovie to access both my camera and my microphone, so I'm not sure why it won't let me record anything. I'm not trying to import anything else, just film using the built-in camera. Anyone know what could be causing this or how to fix it? I have old videos from years ago, so apparently I was able to get it to work in the past, but that was using a different device.