{
    "type": "https://developer.sumup.com/docs/problem/validation-failed/",
    "title": "Bad Request",
    "status": 400,
    "detail": "Validation failed",
    "instance": "9b8eda265e35"
    "failed_constraints": [
        {
            "reference": "checkoutId",
            "message": "Invalid checkout ID: 'not_a_valid_id'"
        }
    ]
}