You will have to check with the meeting organiser, it's him that set the limit. We can't answer for him.
If the lobby is full it mean the meeting size limit is reach, and the lobby is full.
To quote anothers answer on that;
Currently the maximum number of joiners who can wait in the lobby is up to 1/3 of the remaining space in the meeting. Users can get "meeting is full" error message much earlier than users expect. (e.g. meeting size is 250 and 190 people are already in the meeting - in this case, up to 20 people can wait in the lobby. 21st joiner gets "meeting is full" error message and cannot enter the lobby.)