Action Mailer 2.3.5 Vs Action Mailer 3,0

Hello ,
      I been trying to send email in rails 3 and it happen that I
thought of trying in console and found that mail are not been sent and
the ruby code always result in error like

post_connection_check': hostname was not match with the server
certificate (OpenSSL::SSL::SSLError)

then i thought of reverting to actionmailer 2.3.5 and run the same code
lucky it work with no error

Here my both code
1. Code in Action Mailer 3

require "rubygems"
require "action_mailer"
require "ruby-debug"

ActionMailer::Base.delivery_method = :smtp

ActionMailer::Base.smtp_settings = {
   :address => "127.0.0.1",
   :port => 25,
   :domain => 'ubuntu.ubuntu.com',
   :authentication => :plain
}

class Notifier < ActionMailer::Base
  default :from => "sender_email_id"

  # Send reset password notification to user.
  def password_reset_mail(user)
    subject "Password Reset Instructions"
    from "sender_email_id@test.com"
    recipients user
    content_type "text/html"
    sent_on Time.now
    body "RESET your Password"
  end

end

mail_recipient = 'receiver_email_id'

Notifier.password_reset_mail(mail_recipient).deliver

2 . Code in ActionMailer 2.3.5

require "rubygems"
gem 'actionmailer','=2.3.5'
require "actionmailer"
require "ruby-debug"

ActionMailer::Base.delivery_method = :smtp

ActionMailer::Base.smtp_settings = {
   :address => "127.0.0.1",
   :port => 25,
   :domain => 'ubuntu.ubuntu.com',
   :authentication => :plain
}

class Notifier < ActionMailer::Base

  def password_rest_mail(user)

   subject "Password Reset Instructions"
    from "sender_email_id@test.com"
    recipients user
    content_type "text/html"
    sent_on Time.now
    body "RESET your Password"
  end
  end

end

mail_recipient = 'receiver_email_id'

Notifier.deliver_password_rest_mail(mail_recipient)

Any Idea Why is the so

Thanks