Automatically reply every time

I have a rule set up for an employee on vacation, that when an email is received, it will send an automated reply that “I will not be in the office”.
However, the rule only works once. Can it work for each time an email is sent to the person on vacation? Or is it a given that once you get the automated reply, you know that the person is on vacation?The way rules behave and the options you have depend a bit on which mail account type you are using.

Exchange Account

• The Out of Office Assistant will only reply once per sender per time that you turn it on.
• A server-side rule (all rules not marked as client-only) will always reply no matter how often the same sender sends you an email.
• A client-side rule (marked in the name the with “client-only”) will only reply once per sender per Outlook session.

Note: for any of the above automated methods of replying to the Internet, your mail administrator must have it set to be allowed to do so on the Exchange server. For instructions see this guide.

POP3 Account
A rule will only reply once per sender per Outlook session.

Note: for an Exchange client-side rule or a POP3 rule, Outlook must be open in order to process the rules.

Exchange/POP3 Account
For instruction on how to enable the Out of Office Assistant or to configure a rule to automatically reply to incoming emails, see this guide.