电子邮件没有通过谷歌计算引擎上的mandrill发送

Question

我正在使用resque_mailer和mandrill_api为我的rails应用程序发送邮件。邮件在开发模式下交付，但在生产模式下，我收到 Net :: OpenTimeout 错误。完整的错误日志是：

/usr/lib/ruby/2.1.0/net/smtp.rb:541:in `initialize'
/usr/lib/ruby/2.1.0/net/smtp.rb:541:in `open'
/usr/lib/ruby/2.1.0/net/smtp.rb:541:in `tcp_socket'
/usr/lib/ruby/2.1.0/net/smtp.rb:551:in `block in do_start'
/usr/lib/ruby/2.1.0/timeout.rb:91:in `block in timeout'
/usr/lib/ruby/2.1.0/timeout.rb:101:in `call'
/usr/lib/ruby/2.1.0/timeout.rb:101:in `timeout'
/usr/lib/ruby/2.1.0/net/smtp.rb:550:in `do_start'
/usr/lib/ruby/2.1.0/net/smtp.rb:520:in `start'
/opt/gem/ruby/2.1.0/gems/mail-2.6.4/lib/mail/network/delivery_methods/smtp.rb:113:in `deliver!'
/opt/gem/ruby/2.1.0/gems/mail-2.6.4/lib/mail/message.rb:2149:in `do_delivery'
/opt/gem/ruby/2.1.0/gems/mail-2.6.4/lib/mail/message.rb:237:in `block in deliver'
/opt/gem/ruby/2.1.0/gems/actionmailer-4.1.14/lib/action_mailer/base.rb:527:in `block in deliver_mail'
/opt/gem/ruby/2.1.0/gems/activesupport-4.1.14/lib/active_support/notifications.rb:159:in `block in instrument'
/opt/gem/ruby/2.1.0/gems/activesupport-4.1.14/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/opt/gem/ruby/2.1.0/gems/activesupport-4.1.14/lib/active_support/notifications.rb:159:in `instrument'
/opt/gem/ruby/2.1.0/gems/actionmailer-4.1.14/lib/action_mailer/base.rb:525:in `deliver_mail'
/opt/gem/ruby/2.1.0/gems/mail-2.6.4/lib/mail/message.rb:237:in `deliver'
/opt/gem/ruby/2.1.0/gems/resque_mailer-2.2.7/lib/resque_mailer.rb:49:in `perform'

我在production.rb中的smtp设置是

config.action_mailer.delivery_method = :smtp
  config.action_mailer.perform_deliveries = true
  config.action_mailer.raise_delivery_errors = true
  config.action_mailer.default_url_options = { host: "localhost:3000" }

  config.action_mailer.smtp_settings = {
      :address              => "smtp.mandrillapp.com",
      :port                 => 2525,
      :domain               => ENV['domain'],
      :user_name            => ENV['username'],
      :password             => ENV['password'],
      :authentication       => "plain",
      :enable_starttls_auto => true
  }

我做错了什么？提前谢谢。