Anonymous Call Transfer failed

Version:
Trixbox 2.4.0
FreePBX 2.3.1.0
Asterisk 1.4.17

Whenever an anonymous call comes in, it cant be transferred to other extensions and shows “Transfer failed” on the softphone. But the call transfer seems to be working with valid caller id’s. Is there something to be tweaked to get the anonymous call transfer working.

Please advice.

Thanks
Vinod

Please start by providing SIP protocol and verbose console log traces. It may be necessary to provide dialplan contents as well.