Problem presents with calls outbound to provider failing after 10 - 30 seconds. Calls inbound are working. In a packet capture SDP information is sent to the provider multiple times and the call is disconnected.
Go to Setup>Call Routing>VoIP providers
Modify the VoIP provider
Go to the Peer Settings tab, change the Provider type to the opposite setting*
Save the VoIP provider
Modify the VoIP provider
Go to the Peer Settings tab and change the Provider type back
Save the VoIP provider
This should cause the Switchvox to force authentication and calls should work.
*If the provider is set to Provider, change to Peer. If the provider is set to Peer, change to Provider.