To get real-time updates on transactional email metrics, such as Sent and Not Sent, Northern Trail Outfitters should use Event Notification Service. Event Notification Service is a feature that allows marketers to receive real-time notifications of email tracking events via webhooks or APIs. Event Notification Service can help marketers monitor and troubleshoot transactional email sends and ensure compliance with legal obligations. Reference: https://help.salesforce.com/s/articleView?id=sf.mc_es_event_notification_service.htm&type=5