"Getting Curl error: name lookup timed outArray" for geonames(findNearbyPostalCodes) api using with wordpress

Question

I need to get all near by postalcodes with geonames api. I am using the curl for api response.Right now, sometimes I have getting the response from api and sometimes getting the Curl error: name lookup timed outArray.

function getResponse()
{

    $xml = get_data('http://api.geonames.org/findNearbyPostalCodes?postalcode=73301&maxRows=100&username=demo');

    $all_zip_codes = array_keys($xml);

    print_r($all_zip_codes);}

/*Function for getting response from api */

function get_data($url) {

     if(!function_exists('curl_init')) {

    die ("Curl PHP package not installed\n");
    }   

    $ch=curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
    curl_setopt($ch, CURLOPT_TIMEOUT, 15);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    $response = curl_exec($ch);

    if(!curl_errno($ch))
    {
        $info = curl_getinfo($ch);

        echo '<br/> Took ' . $info['total_time'] . ' seconds to send a request to ' . $info['url'];
    }
    else
    {
        echo 'Curl error: ' . curl_error($ch);

    }

    $refineArray = array();
    $parseArray = json_decode(json_encode((array)simplexml_load_string($response)),1);

    foreach($parseArray['code'] as $value) {
        $refineArray[$value['postalcode']] = $value;
    }

    return($refineArray);
}