The call forwards the no answer and busy destinations to another phone on the same system or to the Cisco Unity Express fails when the call is initiated from a Cisco CallManager 5.0 on a SIP Trunk to Cisco CallManager Express. After the phone rings and the timeout (10s) caller gets a fast busy.
Complete these steps in order to resolve this issue:
voice service voip allow-connections sip to sip telephony_service
call-forward pattern .T
Ensure that these commands are added in the Cisco CallManager Express Configuration. When this command is used, then on no answer or busy, Cisco CallManager Express sends a 3XX Moved or REFER back to Cisco CallManager and expect the Cisco CallManager to send a new Invite to Cisco Unity Express.
Configure the call-forward b2bua noan command in order to set the Cisco CallManager Express source address as the 302 redirect contact address. Add this command to the incoming dialpeer:
dial-peer voice 4 voip description ** to HQ ** incoming called-number 40.. !-- Add this b2bua !-- Add this destination-pattern 2...