help debugging ActionMailer with restful_authentication?

In a nutshell, I'm using restful_authentication that emails the user
when they sign up for an account

The development.log file shows the body of the e-mail message being
prepped to send out, but doesn't show confirmation that it made it.

When I use gmail's SMTP server, a Rails exception is thrown because
gmail expects an encrypted connection. A different type of Rails
exception is thrown if I try to connect to a Windows SMTP server on my
local machine. I used Yahoo's SMTP server and no Rails exceptions is
thrown. So, I have a feeling that a connection is made to the Yahoo
SMTP server but, for some reason, no email is delivered.

Could someone advise on how to debug this and find out why it's not
being delivered?

Here's the setup code in environment.rb
ActionMailer::Base.delivery_method = :smtp
ActionMailer::Base.raise_delivery_errors = true

  ActionMailer::Base.smtp_settings = {
:address => "" ,
:port => 25,
:domain => "" ,
:authentication => :login,
:user_name => "patelc75" ,
:password => "irdiktanic" ,

Here's the delivery code:
class UserObserver < ActiveRecord::Observer
  def after_create(user)
  def after_save(user)
    UserMailer.deliver_activation(user) if user.recently_activated?


to use gmail