Do you have configured the failover?
What kind of ? ( Cable or LAn Based)
To have more informations about how to configure; go to failover configuration
in PDM and click in the ? icon.
See the examples; They are good.
Version 622 (when configured) have the capability to maintain the same IP and MAC address when the primary fails.Its great.The routers does not need to have their ARP table reset and the switch and switch back is transparent for the LAN
OBS : Use also statefull failover to not loose connections.Your clients will not see nothing whats happening.
When fully configured the failover from OS 622 is a great product