Check Camera Privacy Settings:

Settings > Privacy > Camera. Ensure camera access is enabled. Verify the specific app has permission to use camera.

Another App Using Camera:

Only one app can use camera at a time. Close Zoom, Skype, and similar apps. Try your camera app again.

Update Camera Driver:

Device Manager > Cameras > Update driver. Or uninstall and restart for automatic reinstallation.

Run Camera Troubleshooter:

Settings > System > Troubleshoot > Camera. Windows attempts automatic diagnosis and repair.

Check Physical Camera:

For external webcams: try different USB port. Check cable connections. Test on another computer.

Check Antivirus Software:

Some security software blocks camera access. Check antivirus settings. Add exception for camera or specific apps.

Conclusion:

Privacy settings are the most common cause. Check permissions first. Another app using camera is frequently overlooked.