@BryanKrause And which room is considered the main chatroom for this site? The other room was frozen in August. (So now only the moderators can post there.)

At the moment, this is the only room associated with this site which is not forzen.

I see that Grand Rounds is in the list with room names on Mathematics Meta.

Of course, I meant to write "frozen" rather than "forzen".

@MartinSleziak Yes, grand rounds is meant to be the main room. I think SE chat has kind of a funky way of keeping a main room open by taking the most recently active and not frozen and some other criteria that tends to identify the right room but fails in cases like this where chat is not active

Yes, I know the details how the system with keeping one room open works.

@BryanKrause All I am saying that if Grand Round is supposed to be the main room, it would be reasonable to unfreeze it. Otherwise regular users cannot post there anything.

It was frozen quite a long time ago:

There was one message in that room since then - the diamond-bearing users can talk in frozen/deleted rooms, but regular users can't.

I'll have to leave now - since I have some duties IRL. But if there is some response here, I should notice it when I check in the evening what's new in my SE inbox.

Have a nice day!

@MartinSleziak Kind of forgot that's a thing I can do on a site I don't mod