Call Transfer issue - CUCM 12.5

[Martin Bieak]

Within the past two weeks or so call transfer stopped working.  Running CUCM 12.5.  There are three possible scenarios we use: 

1. inbound external number -> desk number -> transfer to internal extension
2. inbound external number -> desk number -> transfer to internal extension forwarded to external number
3. inbound external number -> desk number -> transfer to external number

For lines 2 and 3 the call attempts to transfer but it does not complete the transfer and we get the message "Cannot Complete Transfer".   We are unable to do hard transfers and soft transfers we get the the message "Cannot Complete Transfer". 

• Our vendor changed the SIP Relxx Options settings on the SIP profile to Send PRACK for all Messages
• Did resolve the call transferring issue for a short while but then resorted back to not working
• when calls are transferred for line 2 and 3 the end party sees the transferred number answers but there is no party on the other end since the call did not complete transfer and is put on hold. 
• We did a search for bugs and did find one for call transfer but it was for an older version of CUCM

The odd thing is when our header number (in the Cube) is forwarded off of the Carriers switch and not the call manager call transferring works. 

We are in the process of renewing our certs since they will be expiring here soon. 

Any help would be greatly appreciated. 

Marty

[Roger Kallberg]

This is a non CM related issue. It is your service provider that doesn't allow the call as the calling number falls outside of your assigned DID range. This is one of the most common asks in the community. Please do a search for this and you'll find plenty of post on this topic. What you need to know is what the SP expects/requires to allow the call when the calling number is not with-in your allotted DID range.