Notification emails not working on Redmine using SMTP and Gmail - ruby

Question

I have Redmine 2.2.1 installed and running, but I can't get the notification emails to work. I keep getting the following error:
An error occurred while sending mail (getaddrinfo: Name or service not known)
I can't figure out what it is I'm missing. I followed these instructions to set up email notifications using Gmail, but it seems like no matter what changes I make to my configuration.yml file I still get the same error.
This is what my configuration.xml file looks like:
production:
email_delivery:
delivery_method: :smtp
smtp_settings:
tls: true
enable_starttls_auto: true
address: "smtp.gmail.com"
port: 587
domain: "smtp.gmail.com"
authentication: :plain
user_name: "email#mydomain.com"
password: "mypassword"
Everything else is commented out.
I tried changing and removing both the tls and enable_starttls_auto options but changes to the configuration.yml file do not affect the error message.
I also checked for the common mistakes that I found on other forums, like tabs in the configuration file or the production: config being defined twice, etc.
I enabled SMTP on my Gmail account.
I also tried setting up ActionMailer, but I'm not sure what I'm supposed to do with it or if I even need to do that. There was no mention of that being required anywhere. I have it installed and set up but not sure if that's doing anything.
Redmine 2.2.1
ruby 1.8.7 (2012-02-08 patchlevel 358) [x86_64-linux]
Rails 3.2.11
gem version 1.8.24
Amazon AMI Linux
production.log:
Started GET "/redmine/admin/test_email" for 98.xxx.xx.xx at Wed Jan 16 12:28:23 -0800 2013
Processing by AdminController#test_email as HTML
Current user: oscarm (id=3)
Rendered mailer/test_email.text.erb within layouts/mailer (0.1ms)
Redirected to http://mydomain/redmine/settings /edit?tab=notifications
Completed 302 Found in 35ms (ActiveRecord: 0.7ms)
Started GET "/redmine/settings/edit?tab=notifications" for 98.xxx.xx.xx at Wed Jan 16 12:28:23 -0800 2013
Processing by SettingsController#edit as HTML
Parameters: {"tab"=>"notifications"}
Current user: oscarm (id=3)
Rendered settings/_general.html.erb (6.8ms)
Rendered settings/_display.html.erb (9.0ms)
Rendered settings/_authentication.html.erb (5.9ms)
Rendered settings/_projects.html.erb (5.9ms)
Rendered queries/_columns.html.erb (6.5ms)
Rendered settings/_issues.html.erb (12.6ms)
Rendered settings/_notifications.html.erb (6.4ms)
Rendered settings/_mail_handler.html.erb (1.9ms)
Rendered settings/_repositories.html.erb (10.3ms)
Rendered common/_tabs.html.erb (66.2ms)
Rendered settings/edit.html.erb within layouts/admin (67.0ms)
Rendered admin/_menu.html.erb (5.6ms)
Rendered layouts/base.html.erb (19.3ms)
Completed 200 OK in 222ms (Views: 91.3ms | ActiveRecord: 4.3ms)

Answer 1

So I figured out what my issues were...
I kept making modifications to the configuration.yml file and expecting redmine to read it every time I reloaded the page but that wasn't the case. Redmine only reads the configuration files on startup so I had to restart redmine every time I made a change to the config file.
One of the things I tried was installing the action_mailer_optional_tls plugin in redmine/plugin but I finaly found out that this plugin only works for ruby 1.8.6 and I'm using ruby 1.8.7 which has this functionality built-in. After removing the action_mailer_optional_tls directory from redmine/plugin and restarting redmine I was able to send notification emails :-)
So here's my final configuration to make redmine work with gmail:
production:
email_delivery:
delivery_method: :smtp
smtp_settings:
address: "smtp.gmail.com"
port: 587
domain: "smtp.gmail.com"
authentication: :plain
user_name: "myemail#mydomain.com"
password: "mypassword"
enable_starttls_auto: true
Hope this helps someone out there having the same issue.