verify joomla mail settings correct. verify joomla can send emails.
sounds like your site is not setup to send email correct.
Site->Global Configuration->Server- Mail settings
PHP mail works with most hosting providers but if not use smtp and setup the account information then test
I configured the registration using joomla and I received the creation of the account on the administrator email and the activation link in the user email. When I switch to CB to do registration, none of the emails are sent.
It might be a missing configuration. Attached some screen shoots