The default client.conf references localhost:8080/client I think. Not only does the proxy listen on 8000 by default (not 8080), but there is no /client directory under beaker that I can find. Replacing this with the normal fqdn/bkr works.
The beaker-client package is no longer shipping a config in /etc/beaker/client.conf because there's no good default value we can give for HUB_URL. There is an example config in /usr/share/doc/beaker-client-*/client.conf.example instead.