Magento-Cannot use Checkout Endpoint for authentication user

Steps to reproduce

1.  Look at following magento docu a bit https://devdocs.magento.com/guides/v2.4/rest/tutorials/orders/order-create-order.html
2. See following code does not add bearer token for authenticate user https://git.magnolia-cms.com/projects/ADDON/repos/ecommerce/browse/magnolia-ecommerce-magento-connector/src/main/java/info/magnolia/ecommerce/magento/checkout/MagentoCheckoutProvider.java#82,111,143
3. See following code does use correct url follow to magento document https://git.magnolia-cms.com/projects/ADDON/repos/ecommerce/browse/magnolia-ecommerce-magento-connector/src/main/java/info/magnolia/ecommerce/magento/checkout/MagentoCheckoutProvider.java#46-48
4. Execute checkout from postman [Magento] Ecommerce-Endpoint.postman_collection.json

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Expected results

Can execute all method described in https://docs.magnolia-cms.com/product-docs/6.2/Connector-Packs/Commerce-Connector-Pack/E-commerce-REST-endpoints/Checkout-endpoint-API-v2.html for authenticate user

Actual results

500 error is return

Workaround

See temporary branch: https://git.magnolia-cms.com/projects/ADDON/repos/ecommerce/pull-requests?create&sourceBranch=refs%2Fheads%2FECOMMERCE-482

Run with cardId as "mine". See  

Development notes