Notifications are not sending emails at the time they are set up to.

We have notifications set up as follows:

Condition = Down...Latency = 300....On Notification and Off Notification = Email group we set up....We have not set up escalation.....Repeat Every = 60 minutes.

So, the problem is, when a site goes down, we get an email alert that it is down, we also get one when it comes back up. However, if the site is down for 5 hours, we only get the initial email and not one every hour like we have it set up to do. Any ideas? Did we maybe miss something?

configuration email notifications prtg smtp