Signup Emails

Outgoing emails are not working when a new user signs up. 
The mail settings in Joomla configuration work fine and I get an email, CB signups do not generate an email.
Maybe a setting has been changed in error,
Please advise where I should look for the cause. 

Within CB > Configuration > Registration ensure "Registration Email Address" is set to an email address that's a valid outbound email address for your mail server or leave it blank so it uses whatever you've configured in Joomla, which also needs be valid. The email tester in Joomla just emails itself it's not very reliable for testing emails against other domains. Do you receive any email when emailing your user from CB > User Management using Mass Mailer?

Mass Mailer works fine.

Strange, then sign up emails should work without issue as it's all the same API. Are you sure the email didn't go into junk mail? Please be sure a subject and body message are supplied for the registration emails in CB > Configuration > Registration. The defaults should be language keys.