Troubleshooting: Sharepoint "blocked" by Admin Configuration

Introduction:

User gets the screenshot below when attempting to log in to Extranet, stating the administrator has configured Sharepoint to block them if they are not specifically granted access ("assigned") to the application.  

Instructions:

The AAD admin will have to add their security group, or reinstall the security groups, in order to remove this issue.

AAD admins: Cindy Rodriguez & Clarence Thomas