Unable to authenticate outlook address via nodemailer

Question

I am trying to authenticate an outlook email account using nodemailer. But, I continuously get the same message:

{ Error: Invalid login: 535 5.7.3 Authentication unsuccessful [CY1PR03CA0041.namprd03.prod.outlook.com] at SMTPConnection._formatError (/user_code/node_modules/nodemailer/lib/smtp-connection/index.js:591:19) at SMTPConnection._actionAUTHComplete (/user_code/node_modules/nodemailer/lib/smtp-connection/index.js:1320:34) at SMTPConnection._responseActions.push.str (/user_code/node_modules/nodemailer/lib/smtp-connection/index.js:1278:18) at SMTPConnection._processResponse (/user_code/node_modules/nodemailer/lib/smtp-connection/index.js:747:20) at SMTPConnection._onData (/user_code/node_modules/nodemailer/lib/smtp-connection/index.js:543:14) at TLSSocket._socket.on.chunk (/user_code/node_modules/nodemailer/lib/smtp-connection/index.js:694:51) at emitOne (events.js:96:13) at TLSSocket.emit (events.js:188:7) at readableAddChunk (_stream_readable.js:176:18) at TLSSocket.Readable.push (_stream_readable.js:134:10) code: 'EAUTH', response: '535 5.7.3 Authentication unsuccessful [CY1PR03CA0041.namprd03.prod.outlook.com]', responseCode: 535, command: 'AUTH LOGIN' }

Here is my code for nodemailer:

const functions = require('firebase-functions');
var nodemailer=require('nodemailer')

var transporter = nodemailer.createTransport("SMTP", {
auth: {
  user: 'username',
  pass: 'password'
},
service: "hotmail"

exports.sendMail 
=functions.database.ref('requestedChats').onWrite((event)=>{
const data = {
from: '[email protected]',
to: '[email protected]',
subject: 'Hello',
text: 'Test 1235'
}
transporter.sendMail(data, (err, info)=> {
if(err)
  console.log(err)
else
  console.log(info)
})
})'

Answer 1

I had this issue sometime. Check the outlook account, see if the mail service provider sent you an email to enable remote login.

Login attempt are rejected when you're trying to login from a new server (seems to be IP-based checking). Once you manually approve the login attempt, that server will be 'whitelisted'.

Also check for the subject (email title). It should be plain text and should not consist html code.

If you still have this issue or don't received any email from the mail service provider, this is a real issue and better off contact the mail service provider for support.