Nodemailer 535 error when sending from remote server with .env

Goal

Sending emails with nodemailer.

Problem

Sending an email from the remote server ends up with a 535 error (535 Authentication credentials invalid). I'm not using Gmail!

Description

When i logged in at the server, there i pulled the app from my repository, run npm install& npm build, copied the .env file from my local machine to the remote folder and then start the app with node or pm2. When i start the app local it works. On the Ubuntu 18.04 server it doesnt. I have another app on the server and there it works with the same setup (express, dotenv& nodemailer installed for the backend). The port, i set in the .env works without problems.

What i have tried until now:

• Delete the whole remote folder and installed new as described above.
• Installed the app on the server on different directorys: var/www/myapp and home/user/myapp
• Stopped the other app on the server
• Disabled the ufw firewall
• Tried another emailaccount
• Changed the password to a simple one to make sure that it isnt a thing of a special sign

• Checked the settings of my email provider. There isnt any security setting or something like we can find at Gmail

• Instead of using process.env.MAIL& process.env.MAIL_PW i tried it without dotenv and that worked: "myaddress@online.de"& "mypassword". Thats the only thing, that worked until now on this app.

Seems that it is the same problem as described here for instance.

So thats how the function looks like:

const nodemailer = require("nodemailer");

const transporter = nodemailer.createTransport({
  host: process.env.EMAIL_HOST,
  port: 465,
  secure: true,
  tls: {
    ciphers: "SSLv3",
    rejectUnauthorized: false
  },
  auth: {
    user: process.env.MAIL,
    pass: process.env.MAIL_PW
  }
});

const sendMail = mailData => {
  return new Promise((resolve, reject) => {
    const mailOptions = mailData;
    transporter.sendMail(mailOptions, (error, data) => {
      if (error) {
        reject(error);
        console.log(error);
      } else {
        console.log("Message sent: %s", data.messageId);
        console.log("Preview URL: %s", nodemailer.getTestMessageUrl(data));
        resolve(data);
      }
    });
  });
};

module.exports = sendMail;

Thats the .env file:

EMAIL_HOST=smtp.1und1.de
MAIL=myadress@online.de
MAIL_PW=mypassword

PORT=2000

Thats the nginx conf file for this app:

server {

        root         /home/neo/ehilfe/client/build;
        index index.html index.htm index.nginx-debian.html;

        server_name e-hilfe.com www.e-hilfe.com;

        proxy_set_header Host $http_host;

        location / {
        try_files $uri $uri/ /index.html;
        }

        location /api/ {
        proxy_pass http://localhost:2000/api/;
        }

        error_page 404 /404.html;
            location = /40x.html {
        }

        error_page 500 502 503 504 /50x.html;
            location = /50x.html {
        }

        listen [::]:443 ssl; # managed by Certbot
        listen 443 ssl; # managed by Certbot
        ssl_certificate /etc/letsencrypt/live/e-hilfe.com/fullchain.pem; # managed by Certbot
        ssl_certificate_key /etc/letsencrypt/live/e-hilfe.com/privkey.pem; # managed by Certbot
        include /etc/letsencrypt/options-ssl-nginx.conf; # managed by Certbot
        ssl_dhparam /etc/letsencrypt/ssl-dhparams.pem; # managed by Certbot

        }

server  {

        if ($host = www.e-hilfe.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


    if ($host = e-hilfe.com) {
        return 301 https://$host$request_uri;
    } # managed by Certbot


        listen 80;
        listen [::]:80;

        server_name e-hilfe.com www.e-hilfe.com;
        return 404; # managed by Certbot

Thats the error message, i get:

Error: Invalid login: 535 Authentication credentials invalid
    at SMTPConnection._formatError (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:784:19)
    at SMTPConnection._actionAUTHComplete (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:1523:34)
    at SMTPConnection.<anonymous> (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:550:26)
    at SMTPConnection._processResponse (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:942:20)
    at SMTPConnection._onData (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:749:14)
    at TLSSocket.SMTPConnection._onSocketData (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:195:44)
    at TLSSocket.emit (events.js:223:5)
    at addChunk (_stream_readable.js:309:12)
    at readableAddChunk (_stream_readable.js:290:11)
    at TLSSocket.Readable.push (_stream_readable.js:224:10) {
  code: 'EAUTH',
  response: '535 Authentication credentials invalid',
  responseCode: 535,
  command: 'AUTH PLAIN'
}
Error: Invalid login: 535 Authentication credentials invalid
    at SMTPConnection._formatError (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:784:19)
    at SMTPConnection._actionAUTHComplete (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:1523:34)
    at SMTPConnection.<anonymous> (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:550:26)
    at SMTPConnection._processResponse (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:942:20)
    at SMTPConnection._onData (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:749:14)
    at TLSSocket.SMTPConnection._onSocketData (/home/neo/ehilfe/node_modules/nodemailer/lib/smtp-connection/index.js:195:44)
    at TLSSocket.emit (events.js:223:5)
    at addChunk (_stream_readable.js:309:12)
    at readableAddChunk (_stream_readable.js:290:11)
    at TLSSocket.Readable.push (_stream_readable.js:224:10) {
  code: 'EAUTH',
  response: '535 Authentication credentials invalid',
  responseCode: 535,
  command: 'AUTH PLAIN'
}

Maybe anybody has experience with such a issue and can help me?

Finally the link to te repository: https://gitlab.com/leonp5/ehilfe

Thanks in advance :)