We are trying to use consultation transfer. The call is transfered to a VDN where it is queued to skill. If the vector has an announcement before the queue the call gets transfered. If we directly queue the call in the vector the transfer fails.
In all cases we never receive the "connection.disconnect.transfer" event , so we have no way of knowing when the transfer failed. Is there a sample we can see of using the Consultation transfer?

According to the vxml specs, the "connection.disconnect.transfer" event only get thrown for blind transfer.

http://www.w3.org/TR/voicexml20/

Search for "connection.disconnect.transfer" in the above documentation.

Sorry...I realized I was looking at the 2.0 spec. You should be using the 2.1 specs. You do get the "connection.disconnect.transfer" if the called is considered transferred. So in this case, if the transfer fails, you should not get the event. However, if the call is transferred, you should get the event. Try to determine if that is how it behaves.

No, this is not how it behaves. When the call is transfered, the value of the consultation call variable is "connection.disconnect.transfer" but we don't get the event.

Can you post the app's data/log/trace.log for the call?