I have forwarded all calls for an extension to another extension. Forwarding works fine, but if the person the extension is forwarding to is not there, the phone just rings and rings. Is there a setting such that the forwarded call will go into the voicemail box of the person the call is forwarded to?

Mitel 5000 system

For this to work the 2nd extension needs to be forwarded to VM. If the first extension goes to the 2nd and then to VM it should end up in the original extensions box.

The first extension will not follow the forwarding path of the second one. To accomplish this, you need to program separate routing.

The easiest way would be to create a CRA that times out to the second extension. Manually forward the first extension to that CRA; calls will now follow the second extension’s forward path.