Firebase HTTP Cloud Function HTTP error code 403

since 28-03-2020 all my HTTP cloud functions are in error. Before my last update, they were working fine. I changed only few things and after the last deploy I got this error:

<html>

<head>
    <meta http-equiv="content-type" content="text/html;charset=utf-8">
    <title>403 Forbidden</title>
</head>

<body text=#000000 bgcolor=#ffffff>
    <h1>Error: Forbidden</h1>
    <h2>Your client does not have permission to get URL <code>/api/v0/.../</code> from this server. 
</h2>
    <h2></h2>
</body>

</html>

All the changes I did doesn't refer to the HTTP function implementation only in the BI. Is there someone else with the same error? From the Firebase Status Console, it seems that firebase is not experiencing any error https://status.firebase.google.com/

EDIT: added an extract on how I initialize the HTTP cloud functions.

'use strict';

// node import
const cors = require('cors')({ origin: true });
const functions = require('firebase-functions');
const admin = require('firebase-admin');

// Setting timeout and memory for the deploy
const runtimeOpts = {
  timeoutSeconds: 540,
  memory: '2GB'
}


admin.initializeApp(); 

exports.exportMultipleDataToCSV = functions
  .runWith(runtimeOpts)
  .https.onRequest((request, response) => {

    cors(request, response, () => {

      if (request.method === 'PUT')   response.status(403).send('Forbidden!');
      if (request.method === 'DELETE') response.status(403).send('Forbidden!');
      if (request.method === 'POST') response.status(403).send('Forbidden!');

      // BI
      let data = MY-BI;


      response.status(200).set('Access-Control-Allow-Origin', '*').send(data);
    });
});

I'm using the library "request" that I just saw that has been deprecated 2 months ago. It could be the problem? https://www.npmjs.com/package/request