php - 新的 gocardless api http 错误 500

Question

当使用新的 gocardless api 示例时，我可以列出客户，所以我假设我已经正确安装了 composer 但是当我尝试创建订阅的示例时（如下所列）我收到 http 错误 500 有人知道我可能在做什么错误的？

<?php
require 'vendor/autoload.php';

$client = new \GoCardlessPro\Client(array(
  'access_token' => 'my_sandbox_access_token_goes_here',
  'environment'  => \GoCardlessPro\Environment::SANDBOX
));

$client->subscriptions()->create([
  "params" => ["amount" => 25,
               "currency" => "GBP",
               "name" => "Monthly test",
               "interval_unit" => "monthly",
               "day_of_month" => 1,
               "metadata" => ["order_no" => "test1"],
               "links" => ["mandate" => "MA125"]]
]);
?>

谢谢