Why doesn't the message about successful data sending work?

Question

AJAX

The data is successfully sent to the mail and the form is cleared. But the message about sending data is not displayed.
Please tell me where is the mistake.

html code on the page:

<form id="form1" action="#" class="feedback-form">
<input class="input" type="text" name="name" placeholder="Ваше имя" required>
<input class="input" type="tel" name="tel" placeholder="Ваш телефон" required>
<button type="submit" class="btn1">Отправить</button>
<span>Нажимая кнопку «Отправить» вы соглашаетесь на обработку персональных данных.</span>
</form>
<div class="hidden">
<div class="pop" id="pop">
Спасибо за обращение! <br> Заявка отправлена.
</div>
</div>

script

// Маска для формы телефона
    $("input[type='tel']").inputmask({"mask": "[phone]"});
    // <input type="tel" placeholder="+7 (___) ___-___" name="tel">


  //Аякс отправка форм
  //Документация: http://api.jquery.com/jquery.ajax/
  $(document).ready(function () {
    $("#form1").submit(function () {
        $.ajax({
            type: "POST"
            , url: "mail.php"
            , data: $(this).serialize()
        }).done(function () {
            $(this).find("input").val("");
            $("#form1").trigger("reset");
            $.fancybox.open($("#pop"));
            setTimeout(function () {
                $.fancybox.close();
            }, 1500);
        });
        return false;
    });
  });

css form code about successful submission

.pop {
  background-color: #fff;
  max-width: 300px;
  width: 95%;
  text-align: center;
  padding: 40px 15px;
  border-radius: 5px;
  font-size: 24px;
}

.pop .fancybox-close-small {
  display: none;
}

Answer 1

There is no desire to understand fancybox. Replace $.fancybox.open($("#pop"));with $("#pop").show();or open the console and examine the contents for errors