Specifically, I get this error when only 'Read all files and folders stored in Box' is checked under Application Scope when I make a download request to https://api.box.com/2.0/files/429656904704/content:
{"type":"error","status":403,"code":"access_denied_insufficient_permissions","help_url":"http://developers.box.com/docs/#errors","message":"Access denied - insufficient permission","request_id":"eq48x9gk712i6qld"}I do not get this error if I also enable the 'Read and write all files and folders stored in Box' Application scope.