I cannot make a mail system with Nodemailer - node.js

Question

I have been creating the system for several hours. I almost put the project into an end, but somehow I cannot receive any emails after filling the form. Does anyone know what is the cause of this problem ??
First, I installed node.js, then nodemon. I have four main files and a folder in the project folder - app.js, package-lock.json, contact.handlebars, package.json and node_module.
the code below is app.js
const express = require("express");
const bodyParser = require("body-parser");
const exphbs = require("express-handlebars");
const path = require("path");
const nodemailer = require("nodemailer");
const app = express();
// view engine setup
app.engine("handlebars", exphbs());
app.set("view engine", "handlebars");
// Static folder
app.use("/public", express.static(path.join(__dirname, "public")));
// Body Parser Middleware
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
app.get("/", (req, res) => {
res.render("contact", { layout: false });
});
app.post("/send", (req, res) => {
const output = `
<p>You have a new contact request</p>
<h3>Contact Details</h3>
<ul>
<li>Name: ${req.body.name}</li>
<li>Company: ${req.body.company}</li>
<li>Email: ${req.body.email}</li>
<li>Phone: ${req.body.phone}</li>
</ul>
<h3>Message</h3>
<p>${req.body.message}</p>
`;
async function main() {
// Generate test SMTP service account from ethereal.email
// Only needed if you don't have a real mail account for testing
let testAccount = await nodemailer.createTestAccount();
// create reusable transporter object using the default SMTP transport
let transporter = nodemailer.createTransport({
host: "I PUT 1ST SERVERNAME HERE OF HOSTGATOR",
port: 587,
secure: false, // true for 465, false for other ports
auth: {
user: "MY 1ST EMAIL ACCOUNT", // generated ethereal user
pass: "********" // generated ethereal password
},
tls: {
rejectUnauthorized: false
}
});
// send mail with defined transport object
let info = await transporter.sendMail({
from: '"Nodemailer Contact" <MY 1ST EMAIL ACCOUNT>', // sender address
to: "MY SECOND EMAIL ACCOUNT", // list of receivers
subject: "Node Contact Request", // Subject line
text: "Hello world?", // plain text body
html: output // html body
});
console.log("Message sent: %s", info.messageId);
console.log("Preview URL: %s", nodemailer.getTestMessageUrl(info));
res.render("contact", { layout: false }, { msg: "Email has been sent" });
}
main().catch(console.error);
});
app.listen(3000, () => console.log("server started..."));

Answer 1

Ethereal's test SMTP service doesn't send the emails. From their website:
It's a completely free anti-transactional email service where messages never get delivered.
It looks like it lets you view a preview of the sent mail to check your application is working correctly, but to actually send email you need to set up a real SMTP server. You can get SMTP credentials for sending transactional mail from applications from various companies such as SendGrid and Mailgun.