AnsPress User Registration not working.

I have set up anspress on WordPress 4.0.1.
Everything works except for the user registration.
When a user fills out the registration it says it’s sending but no user is actually created and no login occurs.
How do we set it up so that other users can sign up and use the forum?

See also: https://wordpress.org/support/topic/user-registration-not-working-3