Why is nodemailer throwing an error (node.js)?

Question

JavaScript

Hello. This is the error I get:

Listening to 3000
{ Error: queryA ECONNREFUSED smtp.gmail.com
at QueryReqWrap.onresolve [as oncomplete] (dns.js:196:19)
errno: 'ECONNREFUSED',
code: 'EDNS' ,
syscall: 'queryA',
hostname: 'smtp.gmail.com',
command: 'CONN' }