Why is the vkontakte api method not executed if I'm not logged in?

Question

In contact with

Hello. I get the number of likes for my page like this:

VK.api("likes.getList", {type: "sitepage", owner_id: appId, page_url: siteUrl}, function (data) {
    //показать данные
});

If I am logged in to VKontakte, then the method calls the callback and transfers data there, but if I am not logged in, then it does not call the callback. Tell me, please, why is that so?
I can still get the data via JSONP:

$.getJSON('https://api.vk.com/method/likes.getList?type=sitepage&owner_id=appId&page_url=siteUrl&filter=likes&callback=?', function(data,status,xhr) {
    //показать данные
});

But I'm wondering why the method through Javascript does not work. Thanks in advance!