For troubleshooting, please follow the below-mentioned steps.
Step 1. A Test can be taken only on a system that has a camera.
Step 2. Ensure the camera is working.
Step 3. You can visit https://www.onlinemictest.com/
Step 4. to check if your camera is working or not.
Step 5. If your camera is not working, go to Device Manager, check the camera driver. It should be enabled.
Step 6. Check camera privacy setting and allow camera access.
Step 7. Check antivirus and disabled webcam protection.