Webcam still works, body tracking suddenly doesn't

I've been using Character Animator for 8 months with no problems. Last week I opened it up and the camera couldn't identify my body. The handle lines show up randomly all over the screen. The webcam still works. My setup is exactly the same as it has been for 8 months. Lighting is the same. I've tried restarting, reinstalling Character Animator, installing an older version. The body behavior is active. The body icon below the camera is clicked. I've re-calibrated a hundred times. Has anyone had this problem? Any ideas what the problem might be?