The Workflow Notification relies on the user group "Workflow Notification". It must be defined and all users who will receive notifications must be assigned to this group. Since this group is only to facilitate workflow, no security or capabilities need to be set on the group. It is expected that each user will have one or more groups with appropriate security and capabilities.
Once the group is defined and users are assigned, the users must be synced with EPX by opening the Worklist Task Manager tab in the Classic UI and selecting the menu option.