Body
Overview
This rule holds every outgoing message in your Outbox for a designated number of minutes before pushing it live.
Issue
Your Classic Outlook app must stay open during the delay window for the email to go out. If you close the app, the emails will remain paused in your Outbox until you reopen it.
Troubleshooting
Open Outlook and click the File tab in the top-left corner.
Click the Manage Rules & Alerts button.
In the new window, click New Rule.
Under the Start from a blank rule section, select Apply rule on messages I send and click Next.
Do not check any condition boxes on the next screen. Just click Next to apply it to everything.
Click Yes when the prompt asks if you want the rule to apply to every message you send.
In the actions list, scroll down and check the box for defer delivery by a number of minutes.
In the bottom Step 2 box, click the underlined blue phrase "a number of".
Type your preferred delay (e.g., 2 or 5 minutes) and click OK, then click Next.
Add any exceptions if you want (like "except if marked as importance high"), click Next, name your rule, and click Finish.