Debuggen einer SMTP-Timeout-Fehler

Arbeite ich an einem Rails-Projekt, bei Action-Mailer-senden E-mail Kampagnen. Für den moment habe ich getestet, alles mit einem einfachen alten GMail-Konto. Immer näher an die Version jetzt, und ich beschlossen habe zu wechseln, der smtp-server auf unseren lokalen mail-server.

Das ist ja alles schön und gut, bis wir versuchen eigentlich E-mail senden. Mit diesen neuen smtp-server-Einstellungen mit dem mailer nichts tut, sondern time-out:

MY_SMTP_SETTINGS = {
  :address => 'oz.some.server.edu',
  :port => 465,
  :user_name => MY_USERNAME,
  :authentication => :login,
  :password => MY_PASSWORD
}

Dies ist der stack-trace von dem Fehler erhalte ich nach einiger Zeit zu senden versuchen, eine Kampagne:

    Timeout::Error: execution expired
    from /opt/local/lib/ruby/1.8/timeout.rb:60:in `rbuf_fill'
    from /opt/local/lib/ruby/1.8/net/protocol.rb:134:in `rbuf_fill'
    from /opt/local/lib/ruby/1.8/net/protocol.rb:116:in `readuntil'
    from /opt/local/lib/ruby/1.8/net/protocol.rb:126:in `readline'
    from /opt/local/lib/ruby/1.8/net/smtp.rb:911:in `recv_response'
    from /opt/local/lib/ruby/gems/1.8/gems/ambethia-smtp-tls-1.1.2/lib/smtp-tls.rb:19:in `do_start'
    from /opt/local/lib/ruby/1.8/net/smtp.rb:921:in `critical'
    from /opt/local/lib/ruby/gems/1.8/gems/ambethia-smtp-tls-1.1.2/lib/smtp-tls.rb:19:in `do_start'
    from /opt/local/lib/ruby/1.8/net/smtp.rb:525:in `start'
    from /opt/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.2/lib/action_mailer/base.rb:681:in `perform_delivery_smtp'
    from /opt/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.2/lib/action_mailer/base.rb:523:in `__send__'
    from /opt/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.2/lib/action_mailer/base.rb:523:in `deliver!'
    from /opt/local/lib/ruby/gems/1.8/gems/actionmailer-2.3.2/lib/action_mailer/base.rb:395:in `method_missing'
    from /Users/ryan/Development/gsoc/cohort/repo/app/models/freemailer_campaign.rb:39:in `send_campaign'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations/association_collection.rb:364:in `method_missing_without_paginate'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations/association_proxy.rb:219:in `method_missing'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations/association_proxy.rb:219:in `each'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations/association_proxy.rb:219:in `send'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations/association_proxy.rb:219:in `method_missing'
    from /opt/local/lib/ruby/gems/1.8/gems/activerecord-2.3.2/lib/active_record/associations/association_collection.rb:364:in `method_missing_without_paginate'
    from /Users/ryan/Development/gsoc/cohort/repo/vendor/plugins/will_paginate/lib/will_paginate/finder.rb:167:in `method_missing'
    from /Users/ryan/Development/gsoc/cohort/repo/app/models/freemailer_campaign.rb:37:in `send_campaign'

Tun jemand eine Idee, wie ich das genau finden kann mein problem?