找不到定期订阅对象

我有一个表单，用户可以在其中输入他们的信用信息。当他们提交时，我不断收到"找不到对象"。

我检查了密钥和子域，一切都是正确的。可能是什么问题？

public function createSubscription($plan,$token,$email,$fname,$lname,$currency,$starts_at,$company_name)
{
    try {
        $subscription = new 'Recurly_Subscription();
        $subscription->plan_code = $plan;
        $subscription->currency = $currency;
        $subscription->starts_at = $starts_at;
        $account = new 'Recurly_Account();
        $account->account_code = $email;
        $account->first_name = $fname;
        $account->last_name = $lname;
        $account->email = $email;
        $account->company_name = $company_name;
        $billing_info = new 'Recurly_BillingInfo();
        $billing_info->token_id = $token;
        $account->billing_info = $billing_info;
        $subscription->account = $account;
        $subscription->create();
    }
    catch ('Recurly_ValidationError $e){
        throw new CreditDeclined($e->getMessage());
    }
    catch ( 'Exception $e) {
        throw new InvalidGeneral($e->getMessage());
    }
}