Hi. I'm David, and I'm happy to help you.
It is necessary to investigate to understand the reason for this behavior.
To be able to assist you better, please clarify the following:
1 = What is the camera's manufacturer and model?
2 = Please check if there is any message or error code displayed in Device Manager:
- Press Windows + X and select Device Manager.
- Expand Cameras. (If "Cameras" is not listed, check under Other devices or Universal Serial Bus controllers for any item with a yellow warning triangle).
- If the camera or an unknown device is listed, right-click it and select Properties. Check the status message in Device Status.
Quick test: Go to Settings > Privacy & security > Camera and make sure "Camera access" and "Let apps access your camera" are both turned On.
If you prefer, feel free to share a screenshot. Use the shortcut "Windows + Shift + S" to use the screenshot tool.
Looking forward to your reply.