Ruby-on-rails – Sidekiq and rails 4 actionmailer never delivers emails

I've setup sidekiq in a rails 4 application for sending emails and processing background jobs. I have also devise which I am using devise_async and a typical contact form emailer. I am using gmail for sending emails.

If I remove sidekiq, it sends the emails normally through gmail (both devise and contact form) but when I am enabling it, it doesn't work (neither devise_async neither contact form). Sidekiq shows that the background jobs starts and finishes successfully (I also see them through the sinatra app that it's been processed) but the email never been delivered.

In development, the console shows that the emails sent (both with devise_async and from contact form, as they are processed with sidekiq successfully).

What I've already have try:

• I've added the github branch for rails4 of sidekiq (I've also tried the master)
• I've updated and check redis version to be greater than
  2.4 (it's 2.6.14)
• I am running sidekiq with bundle exec sidekiq

but nothing worked. I am using ruby 2.0.0-p247.

I have also setup image processing with sidekiq in this app and works perfectly both in development and in production.

I am not doing anything fancy but I am adding the code for completion:

My mailer code:

  def send_message
   @message = Message.new(message_params)
   if @message.save
     ContactMailer.delay.contact_form(@message.id)
   end
 end

My mailer:

  def contact_form(message_id)
    message = Message.where(id: message_id).first
    @email = message.email
    @message = message.text
    mail(to: "myemail@gmail.com", subject: "Message from contact form")
  end

and my configuration for production (which it works without sidekiq):

  config.action_mailer.delivery_method = :smtp
  ActionMailer::Base.smtp_settings = {
    :address              => "smtp.gmail.com",
    :port                 => 587,
    :domain               => "gmail.com",
    :authentication       => "plain",
    :enable_starttls_auto => true,
    :user_name            => "myusername",
    :password             => "mypassword"
  }
  config.action_mailer.default_url_options = { :host => "mydomain.com" }

And here a typical sidekiq queue:

    /home/john/.rvm/gems/ruby-2.0.0-p247@cluey/bundler/gems/sidekiq-4ed6eba8aff1/lib/sidekiq/rails.rb:14: warning: toplevel constant Queue referenced by Sidekiq::Client::Queue
    2013-07-19T09:47:56Z 20112 TID-1a5mkc INFO: Booting Sidekiq 2.5.2 with Redis at redis://localhost:6379/0
    2013-07-19T09:47:56Z 20112 TID-1a5mkc INFO: Running in ruby 2.0.0p247 (2013-06-27 revision 41674) [i686-linux]
    2013-07-19T09:47:56Z 20112 TID-1a5mkc INFO: See LICENSE and the LGPL-3.0 for licensing details.
    2013-07-19T09:47:56Z 20112 TID-1a5mkc INFO: Starting processing, hit Ctrl-C to stop
    2013-07-19T09:48:11Z 20112 TID-1u2z02 Devise::Async::Backend::Sidekiq JID-4a7e66a14deab112191e4b49 INFO: start
    2013-07-19T09:48:12Z 20112 TID-1u2z02 Devise::Async::Backend::Sidekiq JID-4a7e66a14deab112191e4b49 INFO: done: 1.214 sec
    2013-07-19T09:48:50Z 20112 TID-1u2z02 Devise::Async::Backend::Sidekiq JID-32191822b789f5b6896a5353 INFO: start
2013-07-19T09:48:51Z 20112 TID-1u2z02 Devise::Async::Backend::Sidekiq JID-32191822b789f5b6896a5353 INFO: done: 0.143 sec
2013-07-19T09:49:29Z 20112 TID-1u2z02 Sidekiq::Extensions::DelayedMailer JID-c1911e0c4b72295dc067d57f INFO: start
2013-07-19T09:49:29Z 20112 TID-1u2z02 Sidekiq::Extensions::DelayedMailer JID-c1911e0c4b72295dc067d57f INFO: done: 0.152 sec

I think it has to do with actionmailer and sidekiq but I don't know how to debug, everything seems to work but the emails never delivered.