I've tried to enter the chat room in the past, what? half an hour?
And I get:
Regular connection did not go through.
Trying alternative...
cannot connect to server
Why? did I get banned from the chat? If so, why?

I am using a old version of java, but it still works well, so I doubt it is that.

You're not banned, just keep refreshing the page and you'll get right back in. It happens now and then.

If you were banned you would get a message telling you so.