Hi! Please follow this steps:
- Go to https://outlook.live.com
- Click the gear icon in the upper right to open Settings.
- At the bottom of the quick settings panel, click “View all Outlook settings”.
- Go to Mail > Compose and reply.
- Scroll down to Undo send.
- Ensure the slider is enabled and set to a value this is how long the “Unsend” link will appear after you click Send.
- Click Save if you made any changes.