If a monitor is included in a recipient group, it sends alerts only to recipients from that group. Other recipients will not get alerts from this monitor.
The monitor uses the Primarymonitoring mode, and an error is detected at a non-primary location. These errors are included in reports, but alerts are not sent.
The monitor uses the Round Robin monitoring mode, and an error is detected at only one location. Round Robin monitors trigger alerts only when two or more locations fail during the same interval.
The monitor uses the SLA (MultiPOP) monitoring mode, and the number of locations in the error is less than your configured limit (the SLA Alerts option in your AlertSite UXM preferences).
The recipient’s contact details (email address, phone number and so on) are incomplete or incorrect. Double-check the spelling, make sure phone numbers are specified with area code and country code (1 for US and Canada). See examples in Creating a Recipient.
You configured recipient groups to trigger alerts only for specific error types, and the monitor failed with an error not handled by any recipient group for that monitor. (See Alert Routing by Error Type.)