Failover between the primary and standby BlackBerry® Enterprise Server instances occurs when the standby BlackBerry Enterprise Server determines that its health score is above the promotion threshold and one or more of the following events occurred:

• The standby BlackBerry Enterprise Server receives a health score from the primary BlackBerry Enterprise Server that is below the failover threshold.
• The standby BlackBerry Enterprise Server reads, in the BlackBerry Configuration Database, a health score for the primary BlackBerry Enterprise Server that is below the failover threshold.
• The standby BlackBerry Enterprise Server does not receive a response when it checks the BlackBerry Dispatcher for the health score of the primary BlackBerry Enterprise Server.
• The standby BlackBerry Enterprise Server pings the BlackBerry Dispatcher on the network but cannot determine whether the primary BlackBerry Enterprise Server is running.