A knowledge base article about What Happens when your Voicemail Box is not Activated provided by the UC Berkeley IT Service Hub - Knowledge Portal
What Happens When Your Voicemail Box Is Not Activated
When you have a voicemail box associated with your line but not activated with a recorded greeting, your callers will hear the following message:
Extension X-XXX has not been activated. This message does not mean that your line is disconnected. It simply needs you to record a voicemail greeting to stop your callers from hearing that your line has not been activated.