If you have gone through the GENERAL TROUBLESHOOTING CHECKLIST for the external camera and the camera still won’t work on MAC:
Go to System Preference --> Security and Privacy --> Privacy tab --> Click on the Lock Icon at the bottom left of Security & Privacy Tab --> Enter the system Password (the password used to access computer when computer is first started) > Click on the check box in front of MVProctor.
Camera:
Then click on Automation and check Google Chrome and System Events.
If you still face issues with the webcam try installing Manycam by following the steps given at: