To export a data file to its SFTP containing all subscribers who did not receive their intended email in the last 24 hours, Northern Trail Outfitters should use a Data Extract Activity in their automation. A Data Extract Activity is an activity that allows marketers to extract data from Marketing Cloud and place it in a file on an Enhanced FTP location or an external SFTP location. The Data Extract Activity can use different extract types, such as Tracking Extract or Data Extension Extract, to export different types of data. Reference: https://help.salesforce.com/s/articleView?id=sf.mc_as_data_extract_activity.htm&type=5