I installed odoo 9.0c community on a dedicated server with ubuntu 14.04.
I have an account on register.it for the Mailbox Management.

As recommended by the Register.it guide, in General Settings / Outgoing Mail Servers I wrote:
SMTP server: authsmtp.mydomain.ext
Port: 25
Security: none
Username: smtp@mydomain.ext
Password: mypassword

Obviously mydomain.ext and mypassword have been replaced with the real domain and the real password.

In "general setting", alias domain has been set with the same domain of mydomain.ext

Clicking on "Test Connect" I get: "Test Connection Succeeded! Everything Seems properly set up!"

The problem is that if I try to send an email I get no output, but in "general settings" displays a warning icon and the message: X emails failed, where X in the number of emails that i tried to send. The reason for the failure is: "Run connect () first.".

So I wrote a small python script that uses the same data and that it works properly.

I also tried the same data on a virtual machine server that I created locally with the same version of odoo and ubuntu and sending email is working properly (though the email is sent to the spam folder).

Does anyone have an idea?