Update: As issues like this are pretty rare, if you are experiencing it, please contact us at support@poweradmin.com so we can track down the issue.
Can you reproduce the issue? If so, after you reproduce the issue then look in the Logs directory (usually C:\\Program Files\\PA Server Monitor\\Logs\\ for PA Server Monitor, and a similar location for our other applications) for the PA Server Monitor\_Service\_Log.txt log file. Open the log file and search for the alert notification(start at the bottom. Look at the entries around the notification to see if there ware any errors. The error messages should give you hints to what the issue is. If you are unable to reproduce issue you can wait until the issue occurs again and try to search the log file then.