In the webassist/email folder delete the mail_php.php and mailformatting_php.php files, then edit the UE behavior to recreate them
for the From address, make sure to use a valid email address for your domain, and leave the go to page blank for now.
then add the following codse at line 1 to turn on error reporting:
<?php
error_reporting(E_ALL);
ini_set('display_errrors','on');
?>
and this code in the page body to write the session contents:
<?php var_dump($_SESSION); ?>
the session contents will contain the success or failure for the email for troubleshooting.