When attempting to join meeting audio from a Mac computer after video sharing has already begun, you are unable to join the audio portion of the meeting.
Virtual Office Desktop, Virtual Office Meetings, Mac users
This issue is resolved in the latest version of Virtual Office Desktop (VOD). Download and install VOD, v 5.7.0 build 20238.
This was due to the way in which the app refreshed audio after initializing video sharing on Macs.