Element X doesn’t support the traditional way of making accounts, try use cinny.in to make an account in the browser and then log in with element X. Fluffychat should also present a “create a new account” button above the login button. Make sure to follow instructions in the console for registering the first account.

The federation port not being accessible won’t break local functionality but will break federation, so you won’t be able to talk with other people. Either change the configured port in the well-known file or forward the port via your reverse proxy.

I’d suggest joining the support room via an alt account, you’ll get faster responses.