Safari 15 will not share your microphone with the session, and will eventually suggest you quit and re-join.
When you switch your microphone on, it won’t respond. After several seconds, Collaborate will prompt you to reload the session via a message at the top of the screen. Doing so will have no effect on your microphone.
- Turn your camera on
- Turn your microphone on
- If you don’t require your camera, turn it back off
Alternatively, on macOS, you can use another browser.
Full details are available on the entry on Blackboard’s support site.