Drupal: sendin mail - SMTP error:fputs() [function.fputs]: send of 12 bytes failed...

Greetings everyone,

i am finishing my Drupal 7 site http://wwiivideoarchives.altervista.org
I have the following problem; when a form is sent, i get this error:

Notice: fputs() [function.fputs]: send of 12 bytes failed with errno=32 Broken pipe in SMTP->Authenticate() (line 217 of /membri/wwiivideoarchives/portale/sites/all/modules/smtp/smtp.transport.inc).
Unable to send e-mail. Contact the site administrator if the problem persists.

SMTP module is configured (and the configuration should be ok, because i used the same that i use with another site on another hosting, and both use the same SMTP server and email address).

Just to be sure the problem was not on the SMTP server side, i tried with 2 different SMTP servers (i have 2 emails), both external to altervista .

Do you have any idea about how to fix it? Perhaps Altervista doesn't allow external server? If yes, how can i get an ""altervista email address"" to use with the site?
Thanks in advance for any suggestion

To send email you have to use the PHP's mail() function. SMTP is not available.

PHP is out of my knowledge, but i "fixed" the problem with a turnaround, installing the Module Elastic Mail : at least now i can receive on my mailbox the forms submitted.