I have a customer, which had problems seeing, and admitting participants to Lync meetings.
The problems was also that the presenter could not see the button to admit people who was waiting in the lobby.
The presenter only saw himself when looking at the participants lists, like below.
A debugging trace shows the clients information like below:
The highlighted sections show that this is a large meeting.
On the Lync server this is also confirmed from the powershell with the Get-CsConferencingPolicy
So the problem is that when the conferencing policy has enabled large meeting support, the information about participants is not showen to the presenter and partcipants, and therfor you can’t admit them to the meeting.
Therefore, to solve this specific problem you should disable large meeting with the command:
Set-CsConferencingPolicy –Identity “name” –AllowLargeMeetings 0
After that the Admin button is shown to the presenter like below.
When hosting a large meeting like with 1000 participants it is recommend disabling the lobby function and admitting people when they connect. In addition, the meeting with very large number of participants should be hold on its own conferencing server. To do that you create a new standard pool with the user who will host the meeting.