I've got an elastix box configured and working great, except for one thing. I've got a SIP client installed on my Android phone that can make calls but can never receive them. If I call its extension, it always comes back as "on the phone" for a voicemail. I've tried to figure this out on my own, but am unable to do so. I've tried debugging the peer, but can't come up with usable information. Any help would be greatly appreciated. Thanks!