Error: connect ECONNREFUSED 127.0.0.1:587 nodemailer NodeJS

I'm trying to connect nodemailer to send mails to users after registration. So I turned on IMAP in google settings, than I created app to generate password, and it all works with this serivs. But when I try to connect mail service, I have this error

Error: connect ECONNREFUSED 127.0.0.1:587 at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1187:16) { errno: -111, code: 'ESOCKET', syscall: 'connect', address: '127.0.0.1', port: 587, command: 'CONN' }

mail-service:

import nodemailer from "nodemailer";
class MailService {
  constructor() {
    this.transporter = nodemailer.createTransport({
      host: process.env.SMTP_HOST,
      port: process.env.SMTP_PORT,
      secure: false,
      auth: {
        user: process.env.SMTP_USER,
        pass: process.env.SMTP_PASSWORD,
      },
    });
  }
  async sendActicvationMail(to, link) {
    await this.transporter.sendMail({
      from: process.env.SMTP_USER,
      to,
      subject: "Mail activation " + process.env.API_URl,
      text: "",
      html: `
            <div>
              <h1>For activation click on link</h1>
              <a href="${link}">Click here !</a>
            </div>
          `,
    });
  }
}
export default new MailService();

Where I might made mistake ? Thank you !

I had the same problem and used the dotenv configuration in this file.

import nodemailer from "nodemailer";

// dotenv must be used
import dotenv from "dotenv";
dotenv.config();
// dotenv

class MailService {
  constructor() {
    this.transporter = nodemailer.createTransport({
      host: process.env.SMTP_HOST,
      port: parseInt(process.env.SMTP_PORT, 10),
      secure: false,
      auth: {
        user: process.env.SMTP_USER,
        pass: process.env.SMTP_PASSWORD,
      },
    });
  }
  async sendMail(email, activationLink) {
    await this.transporter.sendMail({
      from: process.env.SMTP_USER,
      to: email,
      subject: `Activation account link ${activationLink}`,
      html: `
        <div>
            <a href="${activationLink}">Click to activate account</a>
        </div>
      `,
    });
  }
}

export default new MailService();