We have several offices in different states that are using Generic SIP trunk from Simple Signal and when one employee calls the extension (DID) of another employee at a different office, the call does not go to voicemail but instead gets, no mailbox ...

Hello.We have five main offices using UC560s connected thru multi-site vpn and are having issues with call transfers.  For example, when one office calls the receptionist at the corporate office and asks to be transferred to CEO, the receptionist ini...