PHP CURL get data diffently from browser

I tried to get data from this URL: https://finance.vietstock.vn/chung-khoan-phai-sinh/VN30F1M/hop-dong-tuong-lai.htm

In browser it displayed all correct data but when I used below code, it required me to log on. Any idea to fix this issue?

Thank you

$cookie = dirname(__FILE__) . "\cookie.txt";
$cainfo = dirname(__FILE__) . "\cacert.pem";

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://finance.vietstock.vn/Account/Login');
curl_setopt($ch, CURLOPT_USERAGENT,'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Ubuntu Chromium/32.0.1700.107 Chrome/32.0.1700.107 Safari/537.36');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, "username=hungtn87@gmail.com&password=ruoutay87");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_COOKIESESSION, true);
curl_setopt($ch, CURLOPT_COOKIEJAR, $cookie);  //could be empty, but cause problems on some hosts
curl_setopt($ch, CURLOPT_COOKIEFILE, dirname(__FILE__) . "\tmp");  //could be empty, but cause problems on some hosts
curl_setopt ($ch, CURLOPT_CAINFO, $cainfo);
$answer = curl_exec($ch);
if (curl_error($ch)) {
    echo curl_error($ch);
}

//another request preserving the session

curl_setopt($ch, CURLOPT_URL, 'https://finance.vietstock.vn/chung-khoan-phai-sinh/VN30F1M/hop-dong-tuong-lai.htm');
curl_setopt($ch, CURLOPT_POST, false);
curl_setopt($ch, CURLOPT_POSTFIELDS, "");
ob_start();
$answer = curl_exec($ch);
if (curl_error($ch)) {
    echo curl_error($ch);
}
curl_close($ch);
$file_content = ob_get_contents();
ob_end_clean();

 print_r($file_content);