Forwarding Rules on the Extension

If a call is getting disconnected when trying to call an extension directly or when an extension is attempting to call their voicemail box, review the Forwarding Rules tied to the extension. 

If the Forwarding Rules are being Forwarded to an Extension, this will cause a loop and the call will fail. 

Instead, this should be forwarded to the voicemail of an extension.

This should stop the loop and, in turn, the call should not disconnect.