Nodemailer status code 500 using createTestAccount()

I'm using default code from Nodemailer page (console added by me):

nodemailer.createTestAccount((err, account) => {
    console.log(err);
    // create reusable transporter object using the default SMTP transport
    let transporter = nodemailer.createTransport({
        host: 'smtp.ethereal.email',
        port: 587,
        secure: false, // true for 465, false for other ports
        auth: {
            user: account.user, // generated ethereal user
            pass: account.pass  // generated ethereal password
        }
    });
});

It returns me the following error:

Error: Invalid status code 500
    at ClientRequest.<anonymous> (/Users/angelodias/GIT/bootcamp/04-iniciando-back-end/node_modules/nodemailer/lib/fetch/index.js:221:23)
    at ClientRequest.emit (events.js:223:5)
    at ClientRequest.EventEmitter.emit (domain.js:475:20)
    at HTTPParser.parserOnIncomingClient [as onIncoming] (_http_client.js:583:27)
    at HTTPParser.parserOnHeadersComplete (_http_common.js:115:17)
    at TLSSocket.socketOnData (_http_client.js:456:22)
    at TLSSocket.emit (events.js:223:5)
    at TLSSocket.EventEmitter.emit (domain.js:475:20)
    at addChunk (_stream_readable.js:309:12)
    at readableAddChunk (_stream_readable.js:290:11) {
  type: 'FETCH',
  sourceUrl: 'https://api.nodemailer.com/user'
}

What am I doing wrong? Is there any bug?

I tried with .then().catch() and it catches the same error.

Running Node v12.14.1 and Nodemailer 6.4.6