The camera is missing only here
The camera works in one application but is absent in another. That observation is already useful: start with the affected application and its permissions. Replacing the hardware would be premature. Record where an image appears and where it does not before changing settings.
Look at the camera itself first. A physical shutter, function key or device switch may block the picture. For an external webcam, check its cable and connection. Keep the connection consistent during a comparison and change one thing at a time. Replacing the cable and application together makes the result harder to interpret.
Separate selection from permission
Windows privacy settings contain camera-access controls. Check the required application or application type; the exact presentation varies with Windows version. Operating-system permission does not replace a website's separate camera permission. Inspect the site settings in the browser you actually use for the meeting as well.
Select the intended camera inside the conferencing application. A laptop can show additional entries or virtual cameras alongside its ordinary webcam. Compare the names with your connected equipment rather than changing everything indiscriminately. The preview should establish whether the selected entry produces the picture you expected.
Remove competing uses for a test
Close other known applications that may be using the camera, saving any open work first. If the camera becomes available, reopen those applications one at a time. This provides a better chance of identifying an interaction than restarting every program and the computer simultaneously, then hoping the problem never returns.
A picture with poor brightness is a different case from an undetected camera. When an image exists, start with lighting and the application's image controls. When the camera is missing, connection, permission and detection are more useful starting points. Keeping those cases separate prevents time spent adjusting picture settings when no video stream is arriving at all.
If the issue remains, record the model, connection, Windows version and exact message. Explicitly mention whether the camera works in another application. A work computer may be subject to centrally managed privacy restrictions; ask the responsible support team to inspect them rather than bypassing them. Once testing is complete, remove access you no longer need. One successful meeting does not require blanket permission for every website you visit afterwards.
