Is there a way to post a message or redirect an expired member to a special page when they try to log in, but are no longer an active member? I am going to be using Xenforo for a private paid site and when a persons membership expires, I want to be able to tell them why they can no longer login and redirect them to the membership sales page. What is the best way to do this?
Create multiple user groups. Only user group A (paid) can view the forums - you can set this in node permissions/user permissions.
User group B (unpaid) should see a notice (that's not dismissible) that informs them they will not be able to do anything until they pay.
You can ALSO use some xen:if *insert template hook* coding to create a custom message on the forum node. It would only display to that group