Microsoft Outlook has an option to delay sent e-mails until a specifc date and time. These e-mails wait in the outbox until they are sent. You can find more information about this functionality on this external link.
This post explains how to sort e-mails in Outlook by ascending or descending delayed delivery date, so you can identified easily the next to be sent.
The post is based on Microsoft Outlook for Microsoft 365 MSO Version 2303.
Step-by-step instructions about how to sort Outlook Outbox by Delayed Delivery Date
- Right-click on the header columns within the Outbox screen, and select “Field Chooser”
- In the Field Chooser dialog, change the drop-down list to “All Fields” (“Frequently-used fields” is selected by default)
- Locate the row “Defer Until”, click it and drag it to the header line in the place where you want to leave it
- Close the Field Chooser dialog
- Click on “Defer until” column header to sort e-mails by this value
- Click it again to swap between ascending and descending order
- Brian Tillman; “Delayed delivery date in outbox“; Microsoft Answers