When an authorized user joins the meeting, dial-in callers will be automatically admitted to the meeting.If they don't enter a leader PIN, they'll be prompted to record their name (if the option to Ask callers to record their name before joining the meeting is set in Microsoft Bridge Options), and then the caller will be informed that the leader has not yet arrived and to please wait in the lobby until a leader joins. If a dial-in user is first to join a meeting, they'll be prompted to enter a leader PIN.
When this option is set to $False (the default value for new users), the Allow unauthenticated callers to be the first people in a meeting check box is not selected, and dial-in conferencing behaves as follows: The remote PowerShell parameter that corresponds to this setting is AllowPSTNOnlyMeeting. The default value for new users of dial-in conferencing is Null, or $False. Until a leader has joined the call, all other callers should wait in the lobby. Organizers of Skype for Business Online Meetings should use this setting when they want to restrict dial-in users from joining calls before a leader has joined the call or when they want users to be prompted to enter a leader PIN if a leader hasn't yet joined the call. If not, then they will wait in the lobby until an authenticated user joins meeting option. When you assign Microsoft as the provider for dial-in conferencing to a user, there's an Allow unauthenticated callers to be the first people in a meeting. If not, then they will wait in the lobby until an authenticated user joins option in the meeting. To resolve this issue, disable the Allow unauthenticated callers to be the first people in a meeting.
When you use a Microsoft dial-in conferencing number to join a Skype for Business Online meeting as the organizer, you experience the following symptoms: