Twilio错误：[HTTP 451]无法获取页面

I am trying to Get the Recent Calls from twilio using theyr PHP library but I get an error and I can't find any info about it.

The script I am using I got it from twilio and it looks like this:

<?php
require __DIR__ . '/twilio-php-master/Twilio/autoload.php';
// Use the REST API Client to make requests to the Twilio REST API
use Twilio\Rest\Client;

// Step 2: Set our AccountSid and AuthToken from https://twilio.com/console
$AccountSid = "Sid here";
$AuthToken = "Token";

// Step 3: Instantiate a new Twilio Rest Client
$client = new Client($AccountSid, $AuthToken);

try {
    // Get Recent Calls
    foreach ($client->account->calls->read() as $call) {
        $time = $call->startTime->format("Y-m-d H:i:s");
        echo "Call from $call->from to $call->to at $time of length $call->duration 
";
    }
} catch (Exception $e) {
    echo "Error: " . $e->getMessage();
}
?>

When I access this file using my browser I get Error: [HTTP 451] Unable to fetch page

Did anybody have the same problem? How did you solve it?