Failed to pass verification (data.success)

I have the following code:

$.ajax(
    {
        type: 'GET',
        url : "chat/updates/",
        async : true,
        cache : false,
        success: function(data){
            if(data.success){
                alert(data)
                thread = data.messages;
                senders = data.senders;
                $.each(thread, function() {
                    if($("#chat-box").is(":visible")){
                        chatbuddy = $("#chat_buddy_id").val();
                        if(this.sender == chatbuddy){
                            li = '<li class="'+ this.type +'"><img src="assets/images/thumbs/'+this.avatar+'" class="avt img-responsive">\
<div class="message">\
<span class="chat-arrow"></span>\
<a href="javascript:void(0)" class="chat-name">'+this.name+'</a>&nbsp;\
<span class="chat-datetime">at '+this.time+'</span>\
<span class="chat-body">'+this.body+'</span></div></li>';
                            $('ul.chat-box-body').append(li);
                            $('ul.chat-box-body').animate({scrollTop: $('ul.chat-box-body').prop("scrollHeight")}, 500);
                            //Mark this message as read
                            $.ajax({ type: "POST", url: base + "chat/mark_read", data: {id: this.msg}});
                        }
                        else{
                            from = this.sender;
                            $.each(senders, function() {
                                if(this.user == from){
                                    $(".chat-group").find('span[rel="'+from+'"]').text(this.count);
                                }
                            });
                        }
                    }
                    else{
                        from = this.sender;
                        $.each(senders, function() {
                            if(this.user == from){
                                $(".chat-group").find('span[rel="'+from+'"]').text(this.count);
                            }
                        });

                    }
                });

                var audio = new Audio('assets/notify/notify.mp3').play();
            }
        },
        error : function(XMLHttpRequest, textstatus, error) { 
            console.log(error); 
        }
    }
);

}, 2000);

method GET is returning me the following JSON:

{"success":true,"messages":[{"msg":"57","sender":"2","recipient":"1","mensagem":"oi","time":"Nov 13, 2015, 6:17 pm","tipo":"receive","nome":""},{"msg":"58","sender":"2","recipient":"1","mensagem":"oi","time":"Nov 13, 2015, 6:18 pm","tipo":"receive","nome":""}],"senders":[{"user":2,"count":2}]}

but there in%% does not pass the check! Can anyone help me?