invitations:

Just recently my invitations for colleagues to join a zoom are being sent under a  colleague's name.  Then I am put in my own waiting room and have to sign in as host.  Some of my colleagues not in my organization will not recognize this name and perhaps not sign in.  How do I fix this?

Also how come we can not use screen sharing to share movies from Amazon Prime, netflix etc.  The sound comes through but the screen is black.  I used to be able to do this1

Thanks