我无法在heroku中使用nodemailer发送电子邮件

const nodemailer = require('nodemailer');
const sgTransport = require('nodemailer-sendgrid-transport');

// 使用SendGrid作为邮件传输服务
const options = {
  auth: {
    api_key: 'YOUR_SENDGRID_API_KEY'
  }
};

const transporter = nodemailer.createTransport(sgTransport(options));

// 邮件选项
const mailOptions = {
  from: 'sender@example.com',
  to: 'recipient@example.com',
  subject: 'Hello from Nodemailer',
  text: 'This is a test email sent from Nodemailer on Heroku.'
};

// 发送邮件
transporter.sendMail(mailOptions, (error, info) => {
  if (error) {
    console.log(error);
  } else {
    console.log('Email sent: ' + info.response);
  }
});