Storefront APIのPayment処理について（checkoutCompleteWithCreditCardV2）

[kwntky]

カスタムアプリ上にて

Storefront APIの checkoutCompleteWithCreditCardV2 を利用して支払いチェックアウトを完了しようとしておりますが、responseにて以下のエラーが返却されます。

Access denied for checkoutCompleteWithCreditCardV2 field. Required access: `unauthenticated_write_checkouts` access scope.

request 

mutation checkoutCompleteWithCreditCardV2($checkoutId: ID!, $payment: CreditCardPaymentInputV2!) {
  checkoutCompleteWithCreditCardV2(checkoutId: $checkoutId, payment: $payment) {
    checkout {
      id
      webUrl
			buyerIdentity {
			  countryCode
	    }
      lineItems(first: 5) {
         edges {
           node {
             id
             title
             quantity
           }
         }
       }
    }
    checkoutUserErrors {
      code
			field
			message
    }
    payment {
			test
			id
    }
  }
}

--------------------------------------------
query
{
	"checkoutId": "${checkoutId}",
	"payment": {
		"billingAddress": {
			"address1": "address1",
			"address2": "address2",
			"city": "city",
			"country": "JP",
			"firstName": "firstName",
			"lastName": "lastName",
			"phone": "81922221111",
			"province": "Tokyo",
			"zip": "1111111"
		},
		"idempotencyKey": "123456789",
		"paymentAmount": {
			"amount": 200,
			"currencyCode": "JPY"
		},
		"test": true,
		"vaultId": "${vaultId}"
	}
}

response

{
	"data": {
		"checkoutCompleteWithCreditCardV2": null
	},
	"errors": [
		{
			"message": "Access denied for checkoutCompleteWithCreditCardV2 field. Required access: `unauthenticated_write_checkouts` access scope.",
			"locations": [
				{
					"line": 2,
					"column": 3
				}
			],
			"path": [
				"checkoutCompleteWithCreditCardV2"
			],
			"extensions": {
				"code": "ACCESS_DENIED",
				"documentation": "https:\/\/shopify.dev\/api\/usage\/access-scopes",
				"requiredAccess": "`unauthenticated_write_checkouts` access scope."
			}
		}
	]
}

Storefrontのアクセススコープを確認したところ、unauthenticated_write_checkouts は有効になっております。

他に対応すべき項目はありますでしょうか？

なお、Shopify Paymentsはテストモードで実行しております。

 

ご存知の方いらっしゃいましたら、お手すきの際にご教授いただけますと幸いです。