Redmine

When i put email.yml configuration file redmine stop to work, doesn't start up again ...

I've an installation of redmine 1.0 on Ubuntu Server and with PostgreSQL as database Server .

Now i'm trying to configure email notification with an account of my Google Apps domain, when i go into Settings -> Email Notification i get this warning message : 
Email delivery is not configured, and notifications are disabled.
Configure your SMTP server in /etc/redmine/<instance>/email.yml and restart the application to enable them.

so, i've inserted an email configuration file (email.yml) in the /etc/redmin/default/ folder like this one :

production:
delivery_method: :smtp
smtp_settings:
address: smtp.gmail.com
port: 587
domain: mydomain.com
authentication: :login
user_name: redmine@mydomain.com
password: myPassword
tls: true

I've also installed the action_mailer_optional_tls plugin and i've also copied the vendor/plugins/action_mailer_optional_tls/lib/smtp_tls.rb to lib/smtp_tls.rb .

Notes :
My redmine folder is located in : /usr/share/redmine
My webserver is nginx and his configuration is :
@
upstream thin_cluster {
server 0.0.0.0:3000;
}

server {
listen 80;
server_name redmine.mydomain.com;
root /usr/share/redmine/public;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Host $http_host; proxy_redirect off;
location / {
try_files $uri/index.html $uri.html $uri @cluster;
client_max_body_size 10M;
client_body_buffer_size 128k;
}

location @cluster {

proxy_pass http://thin_cluster;
    }
   error_page 500 502 503 504 /50x.html;
   location = /usr/share/redmine/public/50x.html {
   root html;
  }
@

The log of nginx web server say :
2011/07/17 11:34:45 [error] 840#0: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 192.168.1.251, server: redmine.mydomain.com, request: "GET / HTTP/1.1", upstream: "http://0.0.0.0:3000/", host: "192.168.1.6"