Why does the callback api vk response come several times?

Question

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I just can not "catch the moment" why the callback api vkontakte returns the result of the request several times.

...
$user_id = $data->object->user_id;
$messGO = "Тест";
msend($messGO,$user_id);
function msend($message, $user = "000000") //000000 - id админа по-умолчанию
{
    global $token, $v;
    $request_params = array('message' => $message, 'user_id' => $user, 'access_token' => $token, 'v' => $v);
    $get_params = http_build_query($request_params);
    file_get_contents('https://api.vk.com/method/messages.send?'. $get_params);
    echo ('ok');
    break;
}

As a result the script fulfills several times. Why "does not catch" the answer "ok"?

Answer 1

On the server settings page in community management, you can view failed requests and their reason.
Most likely, the script outputs something else besides ok, such as a warning or some kind of error, because of this, the answer is considered incorrect.

Answer 2

I also tried to fix this for a long time. There were incorrect response text errors and the commands were passed multiple times. And I found a solution, if it's not very important where to give echo ('ok') then let's immediately after the check (from the official VK script: case 'message_new':). Helped me.