Error: Invalid login: 538 Error: Must issue a STARTTLS command first
    at SMTPConnection._formatError (/var/www/html/nodejs/node_modules/nodemailer/lib/smtp-connection/index.js:591:19)
    at SMTPConnection._actionAUTHComplete (/var/www/html/nodejs/node_modules/nodemailer/lib/smtp-connection/index.js:1320:34)
    at SMTPConnection._responseActions.push.str (/var/www/html/nodejs/node_modules/nodemailer/lib/smtp-connection/index.js:356:26)
    at SMTPConnection._processResponse (/var/www/html/nodejs/node_modules/nodemailer/lib/smtp-connection/index.js:747:20)
    at SMTPConnection._onData (/var/www/html/nodejs/node_modules/nodemailer/lib/smtp-connection/index.js:543:14)
    at Socket._socket.on.chunk (/var/www/html/nodejs/node_modules/nodemailer/lib/smtp-connection/index.js:495:47)
    at Socket.emit (events.js:160:13)
    at addChunk (_stream_readable.js:269:12)
    at readableAddChunk (_stream_readable.js:256:11)
    at Socket.Readable.push (_stream_readable.js:213:10)

var mysql=require('mysql');
var express=require('express');
var cors=require('cors');
var nodemailer=require('nodemailer');
const app=express();
var bodyParser=require('body-parser');
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({
    extended:true
}))
app.use(cors());
const smtp = nodemailer.createTransport({
    service:'ethereal',
    host: 'smtp.ethereal.email',
    port: 587,
    secure:false,
    ignoreTLS:true,
    requireTLS:false,
    auth: {
        user: 'lu4rummljmr72anl@ethereal.email',
        pass: '9SYgdaYyQQPDAPm4CP'
    }
});
app.get('/',function(req,res) {
        return res.send({error:true,message:'working'});
})
app.get('/sent',function(req,res) {
    var mailoptions={
        from:'ewe***@***',
        to:'sdfs**@****',
        subject:'test',
        text:'hai'
    }
    smtp.sendMail(mailoptions,function(err,result) {
        if(err) throw err;
         console.log('Preview URL: %s', nodemailer.getTestMessageUrl(info));
        return res.send('send');
    })
})