Hi there sarah12_.
Welcome to Apple Support Communities. We understand your MacBook Pro camera isn't working just right and we'd like to help. First, try the additional steps in this guide, but you can skip resetting the SMC since you've already done so:
If your built-in camera isn't working on your Mac
Next, if it still isn't working, or you specifically get that error message, let's make sure your camera reports in the hardware information on your MacBook Pro.
Go to the Apple menu () > About This Mac > System Report > Camera. What we are looking for is either "no camera detected" there, or hardware information about your built-in camera.
If you see a message about nothing present in the System Report, you will want to have your MacBook Pro taken in to be physically inspected. Here's how to locate service near you:
Find Locations - Apple
Also our steps on getting your Mac ready for service, if it comes to that:
Get your Mac ready for service
Best regards.