Hi,
Ubuntu installs a default "Virtual Host", which be served by default. You may need to remove this, and ensure that you're accessing the server using the domain name you've configured for Review Board.
To remove the default site, look for a /etc/apache2/sites-enabled and see if there's a file named "000-default" or similar. You'll need to delete that.
You'll also need to make sure that your generated Apache configuration file for Review Board (available in your site directory's conf/webconfs/ — see our
Apache instructions) is symlinked or copied into there.
Then restart Apache and try again.
Christian