If you are trying to access Zoom from the “USC Zoom” link under Course Tools on your Brightspace course navbar and receive an error (like the screen below), the likely reason is you are not logged into your USC Zoom Account. 

Please note: If you cannot locate the “USC Zoom” link under Course Tools from the navbar you will need to contact your instructor

To log into your USC Zoom account, navigate to usc.zoom.us and follow the on-screen prompts.  This will ensure you are logged into your USC Zoom account (as opposed to your personal or other Zoom account you may be using).