Unable to turn on closed captions on iMac

[YokaV]

While I am able to see closed captions in some meetings, I am unable to turn them on in other meetings. I have gone to Accessibility in Settings, but  CC simply would not appear at the bottom of the screen. They did not turn on when the other member present initiated the call, nor when I initiated the call. I did get as far as seeing the sample of a caption, and I turned on "enable." I hope someone can guide me to a solution.