Ability to disable waiting room in meeting is greyed out in security drop-down

[smegrimes]

Hello Community,
I've seen this question posted a few times, but no good answers yet - maybe today's the day????

I would like to disable the waiting room once I start the meeting but when I go into "security" the "enable waiting room" toggle is not highlighted and I'm unable to change it.

I understand that is an admin setting. How do I change that Admin setting so I have the ability to access the control in the "security"?
TIA