Since the issue pertains to the Camera app, the first thing you should do to remediate this is to run the Camera troubleshooting utility. You will find the option for this in the Windows Settings.

If you're running the Windows 10 Mobile Insider preview on a Lumia 930, 1520, or Icon, you can now try slow-motion video with ...

Restart your computer. Plug your webcam into another available USB port. Check your webcam cable. The cable might be damaged. Test your webcam on another working computer. The above steps will let you ...