Подтверждение регистрации через nodemailer

Возникла проблема с подтверждением регистрации, делаю запрос в postman, приходит сообщение о успешности регистрации в postman, но само сообщение на email не приходит.

const nodemailer = require('nodemailer')
const {google} = require('googleapis')
const {OAuth2} = google.auth;
const OAUTH_PLAYGROUND = 'https://developers.google.com/oauthplayground'

const {
    MAILING_SERVICE_CLIENT_ID,
    MAILING_SERVICE_CLIENT_SECRET,
    MAILING_SERVICE_REFRESH_TOKEN,
    SENDER_EMAIL_ADDRESS
} = process.env

const oauth2Client = new google.auth.OAuth2(
    MAILING_SERVICE_CLIENT_ID,
    MAILING_SERVICE_CLIENT_SECRET,
    MAILING_SERVICE_REFRESH_TOKEN,
    OAUTH_PLAYGROUND
)

// send mail
const sendEmail = (to, url, txt) => {
    oauth2Client.setCredentials({
        refresh_token: MAILING_SERVICE_REFRESH_TOKEN
    })

    const accessToken = oauth2Client.getAccessToken()
    const smtpTransport = nodemailer.createTransport({
        service: 'gmail.com',
        auth: {
            type: 'OAuth2',
            user: SENDER_EMAIL_ADDRESS,
            clientId: MAILING_SERVICE_CLIENT_ID,
            clientSecret: MAILING_SERVICE_CLIENT_SECRET,
            refreshToken: MAILING_SERVICE_REFRESH_TOKEN,
            accessToken: accessToken,
        },
    })

    const mailOptions = {
        from: SENDER_EMAIL_ADDRESS,
        to: to,
        subject: "Hello",
        text: 'Hello'
    }

    smtpTransport.sendMail(mailOptions, (err, infor) => {
        if(err) return err;
        return infor
    })
}

module.exports = sendEmail