Auto close tickets after delay

Auto close tickets after delay

We have several monitoring services that report to our support email when there is an issue. Many times we just want to be aware of it but it does not require any action on our part. So, I'm trying to setup Desk to auto close the ticket if it was not assigned to rep after 4 hours but I'm not having any success. Here's what I have:
Automate > Supervise
Active Rule: "Delay Close Notification Tickets"
1 Basic Information
      Name: Delay Close Notification Tickets
      Active: Checked
      Business Hours: Calendar Hours
      Description: Close notification tickets that are not responded to
2 Criteria
      Hours since created > is > 4
      AND
      Ticket Owner > is empty > ${EMPTY}
      AND
      Email > is > notifications@ourdomain.net (this is the email address that those notifications are sent from)
3 Actions
      Close Ticket
            Assignment Rules
                  Fields: Status
                  Values: Closed

I have several tickets that have come in since the rule was created that are unassigned and from that email address but they are not getting closed (some are over 2 days old now).

I did notice that when I go back to Supervise > Rules the toggle switch at the top right corner is off (to the left). I can click it (so it turns green and moves to the right) but after a few hours it is off again.

Please share any corrections or recommendations.
Thank you.

**edit** changed "forwarded to" to "sent from"