In the navigation menu, click Settings on the left
On the Meeting tab, navigate to the Waiting Room option under In-Meeting (Advanced) and verify that the setting is enabled.
Notes:
If the setting is disabled, click the Status toggle to enable it. If a verification dialog displays, choose Turn On to verify the change.
If the option is grayed out, it has been locked at either the Group or Account level, and you will need to contact your Zoom administrator.
Select who you want to admit to the waiting room.
All participants: All participants joining your meeting will be admitted to the waiting room.
Guest participants only: Only participants who are not on your Zoom account or are not logged in will be admitted to the waiting room. If not logged in, they will have an option to log in. Note: If Guest participants only is enabled, you can also enable the option to allow internal participants (users on the account), to admit guests from the waiting room if the host is not in the meeting.