I have set up the Appointments+ plugin and it appears to work correctly for a logged in user. However, the shortcodes do not render for anonymous users (including the add_login tag )
I do NOT use an access control plugins and have tried it under the default TwentyFourteen theme to rule out any common conflicts. This would seem to point to a simple access level issue, but since this is not a membership site, I do not see how any of my settings could be impacting. I did attempt to activate Membership to see if running it with explicit access levels might help, but saw no change in the behavior.