When using the Cancel Messages context menu option, you will receive a screen like this:
The Cancel Messages option, when used at the base Carriers tree, allows you to cancel three types of messages to All Carriers: Past Due, Pending, and Repeating Messages.
Past Due messages are Repeating Messages that should have gone out but haven't and can possibly interfere with the schedule of messages waiting to be sent.
Pending messages are any messages in the queue currently waiting to be sent.
Repeating messages are Scheduled Messages that repeat based on variables passed by the PageGate Client. For more information, please see the PageGate Client section of the manual.
For example, if you have a message set to repeat every hour, choosing the Cancel Repeating Messages option will stop that message from ever happening again. Choosing Cancel Past Due Messages will cancel any previous repeating messages that failed to go out but will not prevent future repeating messages from being sent.