Im using Electron and try to use the amazon SP SPI. Somehow I always get the following error despite that my marketplaceIds are correct.

`// apiCall.js
const SellingPartner = require("amazon-sp-api");
require('dotenv').config({ path: './api.env' });

function apiCall(eanNumbers) {
    (async () => {
        try {
            const spClient = new SellingPartner({
                region: "eu",
                refresh_token: process.env.REFRESH_TOKEN,
                credentials: {
                    SELLING_PARTNER_APP_CLIENT_ID: process.env.CLIENT_ID,
                    SELLING_PARTNER_APP_CLIENT_SECRET: process.env.SECRET_KEY,
                },
            });
            let res = await spClient.callAPI({
                operation: "searchCatalogItems",
                endpoint: "catalogItems",
                marketplaceIds: ["A1PA6795UKMFR9"],
                identifiers: eanNumbers,
                identifiersType: "EAN",
            });
            console.log(res);
        } catch (e) {
            console.log(e);
        }
    })();
}

module.exports = apiCall;
`

I tried different numbers (all of them in the amazon documentation) and other formats in the marketplaceIds field such as JSON Arrays, Strings and Javascript Arrays with strings.