用PHP代码命中的网址无法在服务器上运行

I am using php(Codeigniter) for develop app. I am trying to hit url with php code. On local server its working fine but after host on server its not working. thats my controller code for CI for hit url :-

$channel = curl_init();
        curl_setopt( $channel, CURLOPT_URL, $url);
        curl_setopt( $channel, CURLOPT_RETURNTRANSFER, 1 ); 
        $response = curl_exec ( $channel );
        curl_close ( $channel );

Is it need to change in .htaccess or php.ini. How it will work? Thanks