There are three basic alerts.

'The Check-In Timeout'
The Check-in is an automated process that runs on the station's local streaming computer.  This process syncs the local streaming PC with our central network so that all edits, campaign changes, or other configuration changes are communicated to the local stream.  If a station has been unable to synchronize it's database in xx minutes(usually 25 minutes by default), the system will trip into Check-in Alert Status.  This is not a definite indicator of any stream outage - it could actually be caused by a number of factors, like local internet failure at the station itself, a networking issue at the station or if the Agent application itself has been closed.  In the event of a Time Out Alert, users should alert their local engineering department and have the local staff check the streaming PC to make sure that its operational and all Ando software is running.  If that all checks out, then the local engineers should check the network and internet connections to ensure that there are no local issues preventing the check-in from occurring.  Typically, when the Last Check-in Alert trips, the alert pop-up fromt he Home screen will look like this:

'Spot-Play Timeout'
If a station has been able to check in, but hasn't reported any plays in a couple of hours then this alert is sent.  99% of the time this alert is triggered in conjunction with a No Data Alert.  If that is the case, then the station automation system has stopped sending the needed control data to the streaming PC.  To resolve this, have the local engineers restart the data feed and check the network connection between the station automation system and the streaming computer.  If the Last Spot Played Alert is triggered by itself then this is most likely due to the station being in an intentional commercial free programming period or in Syndicated Programming where no commercial data is sent to the Injector from the automation system.  The only time this alert would be triggered by itself and of a technical nature is if the station recently updated it's automation system and changed the Cart Trigger that the Injector should be looking for to play cover material.  To resolve this, just have your Engineer or Programmers go into the Injector manager section of andomedia.com and use the Cart Trigger Editor to set-up a new, matching cart trigger.  Here is an example:

'Last Data Received'
A Last Data Received alert is tripped when a station's automation system has stopped sending the needed control data from the station on-air machine to the streaming machine.  99% of the time this alert will also trip a Last Spot Played alert within 30 minutes of falling into alert status.  To resolve this issue just have the local engineer reset the data exports and verify that there are no network issues preventing the flow of data from the studio to the streaming PC.  Please note that rebooting the streaming computer most likely will NOT resolve this issue.  99% of the time, No Data alerts are triggered when the there is an issue with the Automation System exports.  Those will need to be restarted on the on air computer in order to resolve this alert.  Most of the time this will lokk like this:

If the alert pop-up window is opened and all three lights are blinking Red, then that usually means that the streaming PC is offline or that there is an internet connection issue at the station.  Conact your local Engineering or IT staff and have them check the streaming PC ASAP.  The alert window will look like this: