Message: CANCELLED ...
A CANCELLED message is produced as soon as some alert criteria is changed or disabled using the
Monitor Options page.
At that point the alert testing process "starts over";
it doesn't matter what the change is. For example, even if the new alert condition is already
met when the change is made, if there is a waiting period it is honored before a new alert is issued.
Also, if sampling is stopped while an Alert is active, the Alert is cancelled.
The "Recent alert history" section of a CANCELLED email is a list of recent ALERT, ALL CLEAR and CANCELLED conditions for this target database.
Help - Monitor Options
ALL CLEAR ...