Adding Own SMTP only channel leads to errror when using


Used Zammad version: 5.1.x
Used Zammad installation type: package
Operating system:

Expected behavior:

  • sends mail

Actual behavior:

Zustellung fehlgeschlagen: “Unable to send email to ‘Customer’: Can’t use Channel::Driver::Smtp: #<OpenSSL::SSL::SSLError: SSL_connect returned=1 errno=0 peeraddr= state=error: wrong version number>”

Steps to reproduce the behavior:

add an SMTP only channel using

mychannel = Channel.create(

area: ‘Email::Account’,

options: {

  inbound: {

     adapter: 'null',

     options: {}


  outbound: {

     adapter: 'smtp' ,

     options: {

        host: "",

        user: "apikey",

        password: "<key removed>",

        port: 587,

        ssl: true,

        domain: Setting.get('fqdn'),

        enable_starttls_auto: true




active: true,

preferences: {

  editable: false


updated_by_id: 1,

created_by_id: 1


i am not sure if the error is a bug or somehow related to the used configuration especially in regarding to ssl / port etc, anything i can do to help solving this issue for me?

i have also configured sendgrid to send notifications from zamamd which works without problem, so it is probably more about how to add the channel corretly then an actual bug

if i use port 465 it works, however sendgrid does recommend using port 587 (and i am using that port when sending notifications from within zammad)