Nodemailer is only sending emails for gmail - node.js

Question

i'm using Oauth2 and nodemailer to send emails using nodejs.
when i send the email to a gmail email ex: example#gmail.com everything is working fine,
but when i try to send the email to a hotmail email ex: example#hotmail.com, it's returning for me a success message, but when i check my email, i see that the email was not sent.
this is my code:
const nodemailer = require('nodemailer');
const { google } = require('googleapis');
const CLIENT_ID = 'My client id';
const CLEINT_SECRET = 'the secret';
const REDIRECT_URI = 'https://developers.google.com/oauthplayground';
const REFRESH_TOKEN = 'the refresh token';
const oAuth2Client = new google.auth.OAuth2(
CLIENT_ID,
CLEINT_SECRET,
REDIRECT_URI
);
oAuth2Client.setCredentials({ refresh_token: REFRESH_TOKEN });
exports.sendEmail = async (email, subject, text, html) => {
try {
const accessToken = await oAuth2Client.getAccessToken();
const transporter = nodemailer.createTransport({
service: 'gmail',
auth: {
type: 'OAuth2',
user: process.env.EMAIL,
clientId: CLIENT_ID,
clientSecret: CLEINT_SECRET,
refreshToken: REFRESH_TOKEN,
accessToken: accessToken,
}
});
const mailOptions = {
from: 'Twitter from AliExpress <process.env.EMAIL>',
to: email,
subject: subject,
text: text,
html: html
};
const result = await transporter.sendMail(mailOptions);
return result
}
catch (error) {
let err = new Error('Email err: '+ error.message)
return err
}
}
Thank you.