Как исправить не работающее всплывающее окно на iPhone 5, iPhone 6s

    $(".download-doc").on("click", function (event) {
      event.preventDefault();
      $(".cd-popup").addClass("is-visible");
      $("body").addClass("stop-scrolling");
    });
    
    //close popup
    $(".cd-popup").on("click", function (event) {
      if ($(event.target).is(".cd-popup-close")) {
        event.preventDefault();
        $(this).removeClass("is-visible");
        $("body").removeClass("stop-scrolling");
      }
    });

.cd-popup  {
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    opacity: 0;
    visibility: hidden;
    z-index: 21;
    -webkit-transition: opacity 0.3s 0s, visibility 0s 0.3s;
    -moz-transition: opacity 0.3s 0s, visibility 0s 0.3s;
    transition: opacity 0.3s 0s, visibility 0s 0.3s;
}
.cd-popup.is-visible {
    opacity: 1;
    visibility: visible;
    -webkit-transition: opacity 0.3s 0s, visibility 0s 0s;
    -moz-transition: opacity 0.3s 0s, visibility 0s 0s;
    transition: opacity 0.3s 0s, visibility 0s 0s;
    overflow-y: hidden;
}
.cd-popup-container {
    position: relative;
    width: 90%;
    max-width: 400px;
    margin: 8em auto;
    background: #d1d8e0;
    border-radius: 3px 3px 5px 5px;
    text-align: center;
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
    -webkit-transform: translateY(-40px);
    -moz-transform: translateY(-40px);
    -ms-transform: translateY(-40px);
    -o-transform: translateY(-40px);
    transform: translateY(-40px);
    /* Force Hardware Acceleration in WebKit */
    -webkit-backface-visibility: hidden;
    -webkit-transition-property: -webkit-transform;
    -moz-transition-property: -moz-transform;
    transition-property: transform;
    -webkit-transition-duration: 0.3s;
    -moz-transition-duration: 0.3s;
    transition-duration: 0.3s;
}
.cd-popup-container .cd-popup-close {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 30px;
    height: 30px;
    opacity: 0.7;
}

.cd-popup-container .cd-popup-close:hover {
    opacity: 1;
}

.cd-popup-container .cd-popup-close::before,
.cd-popup-container .cd-popup-close::after {
    content: "";
    position: absolute;
    top: 12px;
    width: 14px;
    height: 3px;
    background-color: #3d3d3d;
}

.cd-popup-container .cd-popup-close::before {
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    transform: rotate(45deg);
    left: 8px;
}

.cd-popup-container .cd-popup-close::after {
    -webkit-transform: rotate(-45deg);
    -moz-transform: rotate(-45deg);
    -ms-transform: rotate(-45deg);
    -o-transform: rotate(-45deg);
    transform: rotate(-45deg);
    right: 8px;
}

.is-visible .cd-popup-container {
    -webkit-transform: translateY(0);
    -moz-transform: translateY(0);
    -ms-transform: translateY(0);
    -o-transform: translateY(0);
    transform: translateY(0);
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>


<button class="download-doc">OPEN</button>

<div class="cd-popup">
<div class="cd-popup-container">
<div class="andy_input_wrap">
<div class="popup_title__wrap">
<h3 class="popup_title">Sign Up To Download</h3>
<h3 class="popup_title">Sign Up To Download</h3>
<h3 class="popup_title">Sign Up To Download</h3>
<h3 class="popup_title">Sign Up To Download</h3>
</div>
<a href="#0" class="cd-popup-close img-replace"></a>
</div>
</div>
</div>