Information about failover mode on Digium phones and it affects phones.
Why does my Digium phone say Failover Mode, and what does it mean?
Starting in Switchvox SMB 5.5.4 v48406, the Phone Networks setting includes an Alternate Host Address setting. In the event that a Digium phone can no longer reach the Switchvox at the Host Address, the phone will register to the Alternate Host Address. If this happens, the phone will be in Failover Mode, and many of its phone applications will not be available for use. The phone should be able to make and receive calls over the Alternate Host Address until the Host Address becomes available.