When REFER based transfer is used with the Auto Attendant (AA) script on Cisco Unity Express 2.3.1, you might see this error on the Cisco CallManager Express:
%SIP-3-INTERNAL: No subscribe handler registered for "refer"
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The information in this document is based on Cisco Unity Express 2.3.1 with the AA script.
Refer to Configure and Manage the Cisco Unity Express System Auto Attendant for more information on a Cisco Unity Express configuration with the AA script.
The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.
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You might see the %SIP-3-INTERNAL: No subscribe handler registered for "refer" error message in Cisco CallManager Express when REFER based transfer is used with Cisco Unity Express. When a call is routed through the AA, the caller ID displayed is of the AA and is changed to the originating phone number when the call is picked up.
This problem is documented in Cisco bug ID CSCse65665 (registered customers only) .
This happens because Cisco Unity Express 2.3 has the capability to do H.450.2 (full-consult) transfers out of the AA. By default, it calls the destination phone first. Then if it is answered, the call transfer is completed. In order to change this behavior, you need to use the Bye-Also-based call transfer.
Refer to Cisco Unified CallManager Express SRND for more information on call transfer settings and protocols.
Complete these steps in order to use the Bye-Also-based call transfer.
Session into the Cisco Unity Express module using the service-module service- engine x/y session command. Where x/y is the number of the service engine.
Enter these commands:
se-70-0-0-2(config)>ccn subsystem sip
se-70-0-0-2(config-sip)>transfer-mode blind bye-also