We have a pic problem in our room : https://meet.jit.si/efunroom

we have a problem in our room. a third person dials in with the wrong nickname. Writes messages in their name, kicks the participants out of the room and votes on their own. He duplicates the nicknames so that there are suddenly 20
Participants in the room are with the same name. this is not only annoying but also dangerous, if he takes over the tuning without permission, how can this be prevented or where is the mistake

Welcome to the forum.

I assume you’re using the free public instance at meet.jit.si, right? You should set a password for your meetings and also turn on the lobby feature, to make sure only those you invite make it into the meeting.

freddy, thanks for your tip
you are my first answer, thank you very much