Select2 does not work on iOS Device?

I'm using library select2 from Pixels Admin Template. I noticed that it is working well on desktop and android device. Yet, the drop down does not open when viewing on iOS device. I did not know why it is.

$(document).ready(function() {
  var init = [];

  init.push(function() {
    $("#Salutation,#Gender").select2();

    $("#Salutation,#Gender").select2().on("change", () => {
      $(":focus").blur();
    });
  })

  window.PixelAdmin.start(init);
});

body .select2-container.select2-container--default.select2-container--open {
  top: 305px!important;
  left: 22px!important;
}

.select2.select2-container.select2-container--default.select2-container--below.select2-container--open {
  top: auto!important;
}

<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Select2</title>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="pixel-admin.min.js"></script>
<link rel="stylesheet" href="pixel-admin.min.css">
<link href="https://stackpath.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" rel="stylesheet">
<script src="https://stackpath.bootstrapcdn.com/bootstrap/3.3.5/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/select2/3.4.5/select2.css" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/3.4.5/select2.min.js"></script>

<div class="container">
  <div class="row">
    <div class="col-xs-4 col-xs-offset-4">
      <h3>Application Form</h3>
      <form class="form" action="/action_page.php">
        <div class="form-group">
          <label for="GivenName">Given Name:</label>
          <input class="form-control" type="text" id="GivenName">
        </div>
        <div class="form-group">
          <label for="Surname">Surname:</label>
          <input class="form-control" type="text" id="Surname">
        </div>
        <div class="form-group">
          <label for="Salutation">Salutation:</label>
          <select class="form-control" name="" id="Salutation">
            <option value="Mrs">Mrs</option>
            <option value="Mr">Mr</option>
            <option value="Miss">Miss</option>
          </select>
        </div>
        <div class="form-group">
          <label for="Gender">Gender:</label>
          <select class="form-control" name="" id="Gender">
            <option value="Female">Female</option>
            <option value="Male">Male</option>
            <option value="Transgender">Transgender</option>
          </select>
        </div>
        <button type="submit" class="btn btn-default">Submit</button>
      </form>
    </div>
  </div>
</div>

I included pixel-admin js for you here.

Note It works when I use Request Desktop Site feature on iOS device.

Any suggestion? Please kindly help me. Thanks

from Select2 does not work on iOS Device?