Redmine

Dear all,
Our mail server is based on the SSL and port is 465. The email.yml such as below:

  production:
  delivery_method: :smtp
  smtp_settings:
    tls: true
    address: "smtp.xxxx.com" 
    port: 465
    domain: "xxxx.com" 
    authentication: :plain
    user_name: "xxxx@xxxx.com" 
    password: "****"  

The following message show when I send the test mail:
An error occurred while sending mail (execution expired)
Could you please help me how to deal with it?
Many thanks!