I done all the steps to setting up a ip-to-geolocation by using ipstack.com, and read through the documentation. But the object values are returned as 'undefined' in my browser console. This is how the code looks: javascript/jquery code

var ip = '188.124.3.1';
var access_key = 'secret';
$.ajax({
    url: 'api.ipstack.com' + ip + '?access_key=' + access_key,   
    dataType: 'jsonp',
    success: function(json) {
        var city = json.city;
        var zip = json.zip;
        var latitude = json.latitude;
        var longitute = json.longitute;
        console.log(city + ' ' + zip + ' ' + latitude + ' ' + longitute);
//the console says: 'undefined undefined undefined undefined'
        console.log('success!');
        $.ajax({
            type: "post",
            url: "insert_geolocation.php",
            data: {
                    'zip': zip,
                    'lat': latitude,
                    'lng': longitute
                    },
            success: function (data) {
            },
        });
    },
    error: function(html, data) {
        console.log('Error!');
        console.log(data);
    }
});

I use jQuery and JSON output , because I don't know CURL. Can anyone tell me why it return undefined?