amazon-sp-api: Keep getting Unauthorized using sample requests

Keep getting Unauthorized error using sample requests in docs. Should these examples work?

I’m trying to work out if I’m not authenticating properly or whether the API endpoint is giving the error as I’m trying to request data that I don’t have access to (as it’s your data)

Using a brand new marketplace seller account / no products / data.

CustomError: Access to requested resource is denied.
    at SellingPartner.callAPI (/Users/steven/Documents/boilerplate/versiontwo/node_modules/amazon-sp-api/lib/SellingPartner.js:203:13)
    at processTicksAndRejections (node:internal/process/task_queues:93:5)
    at /Users/steven/Documents/boilerplate/versiontwo/packages/amazon/lib/SP-api.ts:19:19 {
  code: 'Unauthorized',
  details: '',
  type: 'error'
}

require("dotenv").config();
require("source-map-support").install();

import SellingPartnerAPI from "amazon-sp-api";

(async () => {
  try {
    const sellingPartner = new SellingPartnerAPI({
      region: "eu",
      refresh_token:
        "XXX",
      options: {
        auto_request_tokens: true,
        auto_request_throttled: true,
      },
    });

    let res = await sellingPartner.callAPI({
      operation: "createReport",
      body: {
        reportType: "GET_FLAT_FILE_OPEN_LISTINGS_DATA",
        marketplaceIds: ["A1PA6795UKMFR9"],
      },
    });

    console.log(res);
  } catch (e) {
    console.log(e);
  }
})();