One User Fine - Two Users, both kicked

Hi all,
So I’ve installed a server for my school to still run sessions with students.
All went well I thought, I’ve installed authentication so the host has more control and can set passwords etc, ive added user and followed the guide.

I am able to start a room, then it asks me for details to be host, which goes in fine and I get to end the room… everything good!

However, when someone else the tries to join the room it kicks both of us out, and says something has gone wrong. It will only work again when just one of us are there.

Any ideas on what I might have missed?

See my answers here : Disconnection after add #secure-domain