Issue: Out of Office is turned on for a user, but a Out of Office notification is not beingsent to internal/external users. You may see the Out of Office message internally BEFORE you send the message in the Outlook notification bar in the new message window.
Cause: Mailbox rules have corrupted or are conflicting with the Out-Of-Office rule in order to send a message to recipients.
Resolution: The resolution is to remove the conflicting rules in the mailbox. To do this:
1. From a run prompt use the following switch: outlook.exe /cleanrules .This will clean client and server rules for the mailbox. This is the fastest way of fixing this issue.
2. You can manually remove each rule in the mailbox.