php curl, ошибка

Пишу парсер на php + curl.

    $ch = curl_init();

            curl_setopt($ch, CURLOPT_URL, $url);
            curl_setopt($ch, CURLOPT_HEADER, 0);
            curl_setopt($ch, CURLOPT_TIMEOUT, 30);
            curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36');
            curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
            curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
            curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 30);
            curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
            curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
            curl_setopt($ch, CURLOPT_REFERER, 'https://www.google.com/');
            curl_setopt($ch, CURLOPT_POST, 0);
            curl_setopt($ch, CURLOPT_COOKIEJAR, $_SERVER['DOCUMENT_ROOT'] . '/cookie.txt');
            curl_setopt($ch, CURLOPT_PROXY, self::$proxy);      

            $result = curl_exec($ch);
            curl_close($ch);
return $result;

Из-за чего ошибка, и $result = false?