If you need to enable auto-reply for external senders too, please (1) click the Outside My Organization (On) tab (2) check the Auto-reply to people outside my organization option (3) type the auto replying message in the below box. In the Automatic Replies dialog box, (1) select the Send automatic replies option (2) check the Only send during this time range option and specify the Start time and End time as you need (3) type the replying message in the below box. Note: If your outlook have not connected to an Exchange Server, you can't find the Automatic Replies option.ΔΆ. In the Mail view, select the exchange account on the Navigation Pane, and click File > Info > Automatic Replies.
If you are using an Exchange account, you can auto reply a specified message for the received emails with setting the Out of Office Assistant while you are away.