When I select to make the forums (and courses) visible to only signed-in (members), new users (not yet signed up) or those who are not signed in get the following message: 

403: Forbidden

The page you were looking for could not be authorized.

Error message:

Due to security restrictions, you are not allowed to access 'Forum' (forum.forum) records. Contact your administrator to request access if necessary.

How and where can I configure odoo to change this behavior and instead redirect to the login page (and redirect them back to the previous page after they have signed in or signed up)?

Thank you for your assistance.