How do I clear an Advanced Alert after I have acknowledged it?
The alert needs to be "Reset". That will depend on the conditions that were set in the definition of the advanced alert. Typically, people set the reset condition to be NOT the trigger condition. So if you trigger when a Node is DOWN. Then Reset when the Node is not DOWN or Reset when Node is UP.
If you can't get it to reset, you can clear the alert directly from the database.
We plan to add a way to manually reset alerts.