1. Check to make sure the webcam is not manually disabled.
2. Check if you have the correct drivers installed. If not, reinstall them.
3. Reboot the computer and try running camera and video call applications again.
4. If the issue persists, check your system device manager to diagnose and troubleshoot any hardware issues.
5. Adjust camera settings in the application you are using to ensure optimal performance.
6. If necessary, adjust the camera angle and lights conditions.