Nodemailer and Oauth2 not working in production

Question

   const nodemailer = require("nodemailer");
    const { google } = require("googleapis");

    const oAuth2Client = new google.auth.OAuth2(
        process.env.GOOGLE_CLIENT_ID,
        process.env.GOOGLE_CLIENT_SECRET,
        "https://developers.google.com/oauthplayground"
    );
    oAuth2Client.setCredentials({refresh_token: process.env.GOOGLE_REFRESH_TOKEN});

    module.exports.sendMail = async (mailOptions) => {
       try {
           const accessToken = await oAuth2Client.getAccessToken();
           const transport = nodemailer.createTransport({
           service: "gmail",
           auth: {
              type: "OAuth2",
              user: process.env.GMAIL_ADDRESS,
              clientId: process.env.GOOGLE_CLIENT_ID,
              clientSecret: process.env.GOOGLE_CLIENT_SECRET,
              refreshToken: process.env.GOOGLE_REFRESH_TOKEN,
              accessToken: accessToken
           }
       });

    await transport.sendMail(mailOptions);

    sendMail()
      .then(() => console.log("Email sent!"))
      .catch((error) => console.log("Email NOT sent! " + error.message));
  } catch (error) {
    return error;
  }
}; 

Hello! This is the code that does auth with google and then sends the email wherever the sendEmail function is called. Everything works smoothly in local, but not in production. I have no idea what i am doing wrong. Thank you for the help.

Answer 1

Better to use SendGrid as a service because you need that for production ( 100 emails/day free ), To ensure the email delivery , They have a reasonable free plan ,. And it’s very easy to install.

For debugging you best use mailtrap ( free ) .