What's wrong with VK API?

Hello I have a problem. I'm trying to get banned users from a group via VK API.

Here is my code:

/**
 * Created by unixwz on 5/30/16.
*/

get_all_groups function(user_id, access_token)
{
 ban_count = 0;
$.ajax({
 type: "POST",
 url: "engine/handler.php",
 data: {"user_id": user_id,
 "access_token": access_token,
 "act" : "get_group"},
 response: "text",
 success: function (data) {
 user_groups = JSON.parse(data) ['response'];
 for(i = 1; i < user_groups.length; i++)
{
$("#all_group").append(
 "<br><label><input value="" + user_groups[i]["gid"] + "" id="group" + i + "" type="checkbox">"
 + user_groups[i]["name"] + " - " + user_groups[i]["gid"] + "</label>",
null);
 get_number_of_banned_users(user_groups[i]["gid"], access_token);
 // get number of banned users for all groups
}
}
});
}

get_number_of_banned_users function(group_id, access_token)
{
$.ajax({
 type: "POST",
 url: "engine/handler.php",
 data: {"group_id": group_id,
 "access_token": access_token,
 "act" : "get_banned_num"},
 response: "text",
 success: function (data) {
alert(data);
}
});
}

Here is the PHP handler:

function get_all_groups($user_id, $access_token)
{
 $curl = curl_init();
 curl_setopt($curl, CURLOPT_URL, "https://api.vk.com/method/groups.get?user_id=". $user_id ."&count=1000&filter=admin,editor,moder&extended=1&access_token=". $access_token ."");
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($curl, CURLOPT_HEADER, 0);
 $response = curl_exec($curl);

 return $response;
}

function get_number_of_banned_users($group_id, $access_token)
{
 $curl = curl_init();
 curl_setopt($curl, CURLOPT_URL, "https://api.vk.com/method/groups.getBanned?group_id=". $group_id ."&count=200&access_token=". $access_token ."");
 curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt($curl, CURLOPT_HEADER, 0);
 $response = curl_exec($curl);

 return $response;
}

if(isset($_POST["act"]))
{
 switch ($_POST["act"])
{
 case "get_group":
 if(isset($_POST["user_id"]) && isset($_POST["access_token"]))
{
 get_all_groups echo($_POST["user_id"], $_POST["access_token"]);
}
break;

 case "get_banned_num":
 if(isset($_POST["group_id"]) && isset($_POST["access_token"]))
{
 get_number_of_banned_users echo($_POST["group_id"], $_POST["access_token"]);
}
break;
}
}

It turns out that the first method groups.get works fine because it only requires a token without access rights, and the second method groups.getBanned always returns {"error":{"error_code":15,"error_msg":"Access denied: no access to this call method","request_params":[{"key":"oauth","value":"1"},{"key":"method","value":"groups.getBanned"},{"key":"group_id","value":"119484487"},{"key":"count","value":"200"}]}} although I autorisoes correctly and the access rights the app expose, but all the same writes that there is no access. Application standalone.

<a href="https://oauth.vk.com/authorize?client_id=5485927&redirect_uri=http://localhost/&display=page&scope=groups&response_type=code">
 <button type="button" class="btn btn-success">Login using OpenID</button>
 </a>

Help solve the problem.