When a call comes in, the call is directed to the auto attendant. From there users are prompted to enter one of four extensions 15, 16, 17, or 0. Whether a user enters 15, 16, or 17, they are transfered to extension 16. When I program a DND button on ext 16, I get the message that the party I am trying to reach is unavailible and that I can enter another extension with the # after. If I then enter 15# or 17# I am transfered to the correct mailboxes. If I dial the extensions internally, I am transfered directly to the correct extension. I checked all the call forwarding as well as the call coverage options. None are set. This is a very small system and utilizes very few features. Very confused, so any leads will be helpful, thank you.