Redmine

Hi all,
I've just installed redmine by apt-get install redmine. Everything looks fine, except I cannot enable email notification.
I've already done everything exactly as the steps according to http://redmineblog.com/articles/setup-redmine-to-send-email-using-gmail/

First, ruby script/plugin install git://github.com/collectiveidea/action_mailer_optional_tls.git

Then, add email.yml in /usr/share/redmine/config/.

1. Outgoing email settings

production:
delivery_method: :smtp
smtp_settings:
tls: true
address: "smtp.gmail.com"
port: '587'
domain: "smtp.gmail.com"
authentication: :plain
user_name: "xxx@gmail.com"
password: "xxx"

But the email notification GUI always show:
Email delivery is not configured, and notifications are disabled.
Configure your SMTP server in config/email.yml and restart the application to enable them.

Can anyone help me?

Best regards