Logitech c920 stops working intermittently

For the past 6 months, I've been using a Logitech c920 webcam with a separate monitor connected to my 2020 Macbook Air, running Catalina v. 10.15.7. Recently, it has stopped working consistently. In the past few weeks, sometimes it works fine. Other times, when I join a Zoom meeting with my video on (and the blue light showing that the webcam is "working"), there is no video. The screen where my video should be is completely black. (It's not a Zoom problem, since Zoom indicates that my video is on.) If I restart the computer, it usually begins to work again. Any suggestions for how to fix this problem?