I need to export current DNN website to static HTML pages. I tried curl PHP code but the issue is I can never successfully login and preserve the session. The response is always the login page. 

My code is below. Thank you for all your help in advance.

$ckfile = tempnam ("/temp", 'cookie.txt');
    
$curl = curl_init();

curl_setopt_array($curl, array(
    CURLOPT_COOKIEJAR=> $ckfile,
    CURLOPT_COOKIEFILE=> $ckfile,
    CURLOPT_RETURNTRANSFER => 1,
    CURLOPT_URL => 'https://www.phenx.org/Default.aspx?tabid=36&ctl=Login',
    CURLOPT_USERAGENT => 'Codular Sample cURL Request',
    CURLOPT_POST => 1,
    CURLOPT_HEADER =>1,
    CURLOPT_HTTPHEADER, array(
        'User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:6.0.2) Gecko/20100101 Firefox/6.0.2',
        'Accept: application/json, application/xml, text/json, text/x-json, text/javascript, text/xml',
        'Content-Type: application/json',
        'Accept-Language: en-gb,en;q=0.5',
        'Proxy-Connection: Close',
        'Cache-Control: max-age=0'
    ),
    CURLOPT_POSTFIELDS => array(
        dnn_ctr_Login_Login_DNN_txtUsername => 'USERNAME',
        dnn_ctr_Login_Login_DNN_txtPassword => 'PASSWORD',
        dnn_ctr_Login_chkCookie =>'1'

    )
));


    // Send the request & save response to $resp
    $response = curl_exec($curl);