$_FILES приходит пустой

Проблема в заголовке.

Настройки php.ini

file_uploads On
max_file_uploads 192M
upload_max_filesize 192M
upload_tmp_dir /tmp

Форма:

<form action="#" class="form" enctype="multipart/form-data">
  <input name="MAX_FILE_SIZE" value="30000" type="hidden">
    <label>
        <span>Ваше имя</span>
        <input name="name" required="" type="text">
    </label>
    <label>
        <span>Ваш телефон</span>
        <input name="phone" required="" type="text">
    </label>
    <label class="file-label">
        <span>Прикрепить файл</span>
        <input name="file" id="file" type="file">
    </label>
    <button class="btn">Отправить</button>
</form>

JS:

$("form.form").on("submit", function(e){
    e.preventDefault();
    var form = $(this),
        data = $(this).serialize(),
        url = 'mail.php';
    $.ajax({
            type: 'POST',
            url: url,
            data: data,
            cache: false,
            async: false,
            contentType: false,
            processData: false,
            mimeType: "multipart/form-data",
            dataType : "json"
            }).done(function( msg ) {
                console.log(msg);
                setTimeout(function(){
                    form.trigger("reset");
                }, 3000);
            });
        });

PHP:

$uploaddir = $_SERVER['DOCUMENT_ROOT'].'/uploads/';
$uploadfile = $uploaddir.$_FILES['file']['name'];
move_uploaded_file($_FILES['file']['tmp_name'], $uploadfile);