Try leaving the SMTP server address and the port number blank, or enter localhost and 25
also, you have the from address set to use a dynamic binding. like i said before, most hosts require the from address to be a valid email address for your domain.
to test the email status, add the following code on the contacts.php page:
<?php @session_start(); var_dump($_SESSION); ?>
this write the session contents to the page including the status of sending the email.