There are a number of reasons this could be happening, we suggest trying the following:
1. Make sure that you've provided necessary permissions to access your camera
2. Check that your webcam is properly connected to your console or PC.
3. If using a PC, try connecting your webcam to a different USB port.
4. Make sure your webcam is selected in Lightstream Studio's 'Camera' settings.
5. Try restarting your console or PC, then reopen Lightstream Studio.
If problems persist, contact our support team.