Using Classic Outlook on Windows for personal email, calendar, and contact management
Dear User2993,
Good day! Thank you for posting to Microsoft Community.
I understand your query, but since the automatic reply feature will be populated after the massage arrives in the mailbox, the feature you are querying (notifying the sender when typing your email account in the To field) doesn't seem feasible in Outlook at the moment.
However, as a workaround you may try to set out of office rule in outlook to reply for all incoming emails instead of setting Automatic replies feature ON. Once you set out of Office rule in outlook as long as your computer is on and outlook is running, the rule will reply to all incoming email with the message you specified in the template body. If you haven't check it yet, you can refer to Use rules to create an out of office message - Microsoft Support and set the rule, then check if there is any difference.
If you have any other question or I have got you wrong, please feel free to let me know.
Thank you for your precious time. Have a nice day.
Sincerely,
Libeamlak | Microsoft Community Moderator