The recipient must have an active connection with Exchange. When Cached Exchange Mode is enabled and the recipient is working off-line, the recall process will fail. The original message must arrive in the Inbox folder of the recipient. When it got moved via a rule, recalling the message is not possible.

How do I know if my email recall was successful?

When recalling the email, make sure to tick the following option: Tell me if recall succeeds or fails for each recipient. As a result, Outlook will send you a notification about each recipient. If the recall was successful, you'll see a Recall Success note in front of the subject.

Why is recall not working?

Message Recall will not be successful if: The recipient is not using Outlook. The recipient is not logged on to the mail service provider. The message has been moved from the Inbox.