NodeJS / Google Cloud Function — CSRF-verification failed response from server

I get a "CSRF-verification failed" response from the server.

I don't get why tho. I'm trying both using Google Cloud Function and running the code on my own machine.

Error Reponse

CSRF-verification failed. Try again.

Code

const axios = require('axios')
const to = require('await-to-js').default

const getAPI = () => {

    // basic auth
    const auth = {
        username: "API USER",
        password: "API PASSWORD"
    }

    const instance = axios.create({
        baseURL: "https://sandbox.billogram.com/api/v2/invoice",
        auth,
        headers: {
            Referer: "http://localhost:3000/"
        }
    })
    return instance
}

const createInvoice = async () => {
    const api = getAPI()
    const [err, res] = await to(
        api.post('invoice', {
            "items": [
                {
                    "description": "Item 1",
                    "quantity": 2,
                    "unit_price": 100
                }
            ],
            "currency": "SEK",
            "customer": {
                "first_name": "John",
                "last_name": "Doe",
                "email": "john.doe@example.com",
                "phone": "555-555-5555"
            }
        })
    )
    if (err) return console.log('ERR', err.message, err.response.data)
    console.log(res.data)
}

createInvoice()
    .then((res) => {
        console.log(res)
    })

Question

• Can you try to explain how come?

• Also how to find the correct Referer from Google Cloud and local development machine?

Many thanks in advance!

It was me who relied on ChatGPT code too much. The API was updated and the API endpoint had been changed.