Error: SQLSTATE[HY000] [2002] Can't connect to server on '147.45.138.167' (115)
<script src="https://code.jquery.com/jquery-3.6.0.min.js"></script>
<script>
function getSubscriptionUrl(username) {
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "get_subscription_url.php", true);
    xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
    xhr.onreadystatechange = function () {
        if (xhr.readyState === 4 && xhr.status === 200) {
            var response = JSON.parse(xhr.responseText);
            var button = document.getElementById('btn_' + username);
            var qrBtnSpan = document.getElementById('qr_btn_' + username);
            if (response.subscription_url) {
                button.innerHTML = 'Copy';
                button.onclick = function() {
                    copyToClipboard(response.subscription_url);
                };
                qrBtnSpan.innerHTML = `<button class="qr-code-icon" data-url="${response.subscription_url}">QR Code</button>`;
                $('.qr-code-icon').on('click', function() {
                    var url = $(this).data('url');
                    $('#qrCodeImage').attr('src', 'https://api.qrserver.com/v1/create-qr-code/?size=300x300&data=' + url);
                    $('#qrCodePopup').modal('show');
                });
            } else {
                button.innerHTML = "N/A";
            }
        }
    };
    xhr.send("username=" + encodeURIComponent(username));
}

function copyToClipboard(url) {
    var textarea = document.createElement("textarea");
    textarea.value = url;
    document.body.appendChild(textarea);
    textarea.select();
    document.execCommand("copy");
    document.body.removeChild(textarea);
    alert("Subscription link copied to clipboard!");
}

$(document).on('click', '.qr-code-icon', function() {
    var url = $(this).data('url');
    $('#qrCodeImage').attr('src', 'https://api.qrserver.com/v1/create-qr-code/?size=300x300&data=' + url);
    $('#qrCodePopup').modal('show');
});
</script>

<!-- Modal HTML for QR Code -->
<div id="qrCodePopup" class="modal" tabindex="-1" role="dialog">
    <div class="modal-dialog" role="document">
        <div class="modal-content">
            <div class="modal-header">
                <h5 class="modal-title">QR Code</h5>
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                    <span aria-hidden="true">&times;</span>
                </button>
            </div>
            <div class="modal-body">
                <img id="qrCodeImage" src="" alt="QR Code">
            </div>
            <div class="modal-footer">
                <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
            </div>
        </div>
    </div>
</div>

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>