Error: getaddrinfo ENOTFOUND mail.square.io mail.square.io:587
at errnoException (dns.js:28:10)
at GetAddrInfoReqWrap.onlookup [as oncomplete] (dns.js:76:26)

const functions = require('firebase-functions');
const nodemailer = require('nodemailer');
const smtpTransport = require("nodemailer-smtp-transport");

const mailTransport = nodemailer.createTransport(
      smtpTransport({
          host: "mail.square.io", // hostname
          port: '587', // port for secure SMTP
          //secureConnection: false, // TLS requires secureConnection to be false
          auth: {
              user: 'hello@square.io',
              pass: 'square123'
          },
          tls: {
               rejectUnauthrized: false
          }
      }));