Blackboard Collaborate Ultra

I'm a professor, and my program has moved to using Blackboard Collaborate Ultra for meetings, including classroom sessions. When I sign in, my camera works, but I have to call in with my phone to hear the audio. Also, I see documents that others have shared, but I don't see anything when people share an application (e.g. when they open Blackboard on their screen). I can't find anything in the help sections on Blackboard.

I have a 2016 MacBook Pro running Catalina.