Two suggestions:-
1. As already suggested it may be being caught in your registrant's SPAM filter. If they're using Outlook you can add an email address or domain to a "Safe Senders' List" or some such description. Other mail systems should have a similar facility, sometimes called a "White List" (cf a "Black List" of barred addresses).
2. Some web hosts, including mine, Fasthosts, have built in anti-spam blocking systems which can impact the Sendmail routine used by PHPFusion. I modified Sendmail.php as follows:
The new line is:
ini_set("sendmail_from"," root@mydomain.co.uk "where
mydomain.co.uk is the name of your domain...
<?php
/*---------------------------------------------------+
| PHPFusion 6 Content Management System
+----------------------------------------------------+
| Copyright © 2002 - 2005 Nick Jones
| http://www.php-fusion.co.uk/
+----------------------------------------------------+
| Released under the terms & conditions of v2 of the
| GNU General Public License. For details refer to
| the included gpl.txt file or visit http://gnu.org
+----------------------------------------------------*/
if (!defined("IN_FUSION"
) { header("Location:../index.php"
; exit; }
/* sendemail parameters
$to_name - recipient's name
$to_email - recipient's email address
$from_name - sender's name
$from_email - sender's email address
$subject - e-mail subject
$message - e-mail body
$type - plain or html (must be specified if $cc or $bcc is set)
$cc - carbon copy recipients (must be specified if $bcc is set)
$bcc - blind carbon copy recipients
*/
ini_set("sendmail_from"," root@mydomain.co.uk "
;
function sendemail($to_name,$to_email,$from_name,$from_email,$subject,$message,$type="plain",$cc="",$bcc=""
{
global $settings,$locale;
... rest of standard sendmail.php file
Hope this helps.