ActionMailer not send and not generate errors

I have insert in envirmonment.rb

ActionMailer::Base.delivery_method= :sendmail

and i have created a mailer model:

class MyMailer < ActionMailer::Base
def mail_authentication(user)
from “[email protected]
recipients user.mail
subject “| NERTO | Conferma Registrazione”
body :user => user
end
end

with his template

For sending a letter i have insert in a controller this:
MyMailer.deliver_mail_authentication(@user)

but the mail don’t is sent.
In the console there are no errors.

Why?
Where is the problem?

i try also with:
ActionMailer::Base.smtp_settings = {
:address => “smtp.nerto.it”,
:port => 25,
:user_name => “[email protected]”,
:domain => “www.nerto.it”,
:password => “*****”,
:authentication => :plain
}

but it the same thing.
Thanks