Hello,
Please try using the “Windows Camera Troubleshooter” described in the support article below.
Camera app shows error "0xA00F4244 NoCamerasAreAttached"
Alternatively, press the Windows key + I to open Settings.
Go to System > Troubleshoot > Other troubleshooters, and run the Camera troubleshooter.
Also, perform a full shutdown by holding the Shift key while selecting Shut down.
After turning the PC back on, check whether the camera issue has been resolved.