For some reason, whenever I create a private room for my alliance, it disappears after a while. The first few times I thought it was because of inactivity, but then today it closed while we were inside the room.

Yeah i was experimenting with the chat today, (my first few times there) and whenever i made a room, it closed after a while. I always thought this was due to inacitvity though... I'm sure there's some reason for it.

There is.... the rooms you make are temporary.

Only alliances can PM me to make a permanent room for them with password.
Your own rooms dissapear when you leave them.