Hi 

I am having the same problem i am using odoo at ubuntu 14.04

my Outgoing Mail Servers details are

SMTP:smtp.gmail.com

SSL/TLS is selected

port :465

at TEST CONNECTION it said Successfull ...

but still not been able to send the mail using Mass Mail from localhost

Did you delete the default outgoing server "localhost" ?

First of all did you verified outgoing server ? 

1. To verify outgoing server : 

1) Go to Settings >> Technical >> Email >> Outgoing Server

2) Open your configured server. 

3) Click on "Test Connection" button. Is your connection successful ?

2. To check your server must be in low priority 

Sometimes when you define your outgoing server, it is having higher priority then default one of Odoo. Please make your server as Priority "1". Set bigger priority for rest of others. If multiple outgoing servers are there then OpenERP selects which is having low priority or of lower ID in case if priority are same. So try to follow this way by seting lowest priority of your outgoing server.

3. Give me your log over here.

If above both ways will not work then I guess some of the SMTP library problems because you are using windows. So paste your log over here. So I can trace what is the problem.

I am sure you will get your solution within first 2 ways. If not then we are here for you ! ;)

May this answer help you !