mail relay: do not accept TLS servers

haraka can only relay via STARTTLS

src/mail.js

@@ -97,13 +97,11 @@ const assert = require('assert'),
     services = require('./services.js'),
     settings = require('./settings.js'),
     shell = require('./shell.js'),
-    smtpTransport = require('nodemailer-smtp-transport'),
     superagent = require('superagent'),
     sysinfo = require('./sysinfo.js'),
     system = require('./system.js'),
     tasks = require('./tasks.js'),
     users = require('./users.js'),
-    util = require('util'),
     validator = require('validator'),
     _ = require('underscore');
 
@@ -237,7 +235,8 @@ async function checkSmtpRelay(relay) {
         connectionTimeout: 5000,
         greetingTimeout: 5000,
         host: relay.host,
-        port: relay.port
+        port: relay.port,
+        secure: false // haraka relay only supports STARTTLS
     };
 
     // only set auth if either username or password is provided, some relays auth based on IP (range)
@@ -250,9 +249,9 @@ async function checkSmtpRelay(relay) {
 
     if (relay.acceptSelfSignedCerts) options.tls = { rejectUnauthorized: false };
 
-    const transporter = nodemailer.createTransport(smtpTransport(options));
+    const transporter = nodemailer.createTransport(options);
 
-    const [error] = await safe(util.promisify(transporter.verify)());
+    const [error] = await safe(transporter.verify());
     result.status = !error;
     if (error) {
         result.value = result.errorMessage = error.message;