Alerts are messages about a job, source server, or destination server in the Backup Group, and indicate that a problem exists that requires a response from the user. You can respond to one alert at a time, multiple alerts, or to all alerts at once.
Alert history lists the alerts to which an administrator responded. Alerts remain in history for 30 days by default unless you delete them. You can delete one or more alerts in history.
When you view active alerts or alert history, you can change the order in which the information displays. The list can be sorted in ascending or descending order by any column.