Chatterbox requires registration is enabled on a homeserver, which causes some usability issues on private hosts.

While it's possible (at least on Synapse) to set your homeserver to registration-enabled but protected by a token (and in fact this is the default) clients are not aware that this is a flow intended for chatterbox users, causing issues like https://github.com/vector-im/element-web/issues/23560.

The setup for this problem is fairly simple:

- Have a host that is effectively registration disabled, but with a secret token for your chatterbox users. You could also have it be SSO enabled.
- Clients are presented with the option to register, but only after registration does this become apparent that you can't use it.

It's not really a chatterbox problem per-se, but due to our requirements of this token it does make it a bit more awkward for everyone else.