What does MEETING_FAIL_AUTHORIZED_USER_NOT_INMEETING mean? How do I fix/avoid it?

I have a fairly simple app that is a bridge between Zoom and our product, using the Meeting SDK, that allows our

product to send and receive A/V to/from Zoom.  I’m seeing a strange problem that I don’t understand.  If user A starts

a meeting, then if I go to our app and login to Zoom as A, our app can join the meeting.  Same with user B starting and

joining a meeting.  However, if A starts the meeting and B tries to join I get the error  “Authorized user not 

in meeting.”, MeetingFailCode::MEETING_FAIL_AUTHORIZED_USER_NOT_INMEETING. 

I have no idea what “Authorized user” means.  The app has been added to both user accounts and both user accounts

are in the same domain.  

The really strange part is that if I start a meeting as either A or B, and I don’t log into Zoom on our app, I can join

anonymously.  It works just fine.  Does anybody know what’s going on?