You have to set your configuration about mails in preference
correctly. Could you tell me how you have input in the
control panel? And, to solve, I need to know your server's
environment.
Server Name Japan.nswebhost
O. System Linux
Kernel version 2.6.17.11-grsec
Machine Type i686
Apache version 1.3.37 (Unix)
PERL version 5.8.7
Path to PERL /usr/bin/perl
Path to sendmail /usr/sbin/sendmail
PHP version 4.4.3
MySQL version 4.0.27-standard
Legacy Preferences are set to default install : PHP (mail)
with user webmaster (xoopscube@xoopserver.com)
Also tested Xoops 2.0.16 on the same server and it works.
There's no Error message or log file on the server.
It stopped to work since my last update of XC (january 2007).
Server Name Japan.nswebhost
O. System Linux
Kernel version 2.6.17.11-grsec
Machine Type i686
Apache version 1.3.37 (Unix)
PERL version 5.8.7
Path to PERL /usr/bin/perl
Path to sendmail /usr/sbin/sendmail
PHP version 4.4.3
MySQL version 4.0.27-standard
Legacy Preferences are set to default install : PHP (mail)
with user webmaster (xoopscube@xoopserver.com)
Also tested Xoops 2.0.16 on the same server and it works.
There's no Error message or log file on the server.
It stopped to work since my last update of XC (january 2007).
User registration also fail on the following environment:
Operanting System Free BSD
Kernel Version FreeBSD 5.5-PRERELEASE
Machine Type i386
Apache 2.0.55
MySQL Version 4.1.18
PHP Version 5.1.2
Perl Version 5.008
Pathto sendmail /usr/bin/sendmail
After ad to DB user registration
the process ends without send the email to new user.
No information from debug or log.
This issue is moved to sf.net
[ 1709878 ] <sf.jp> PHP Mail doesn't Work
http://sourceforge.net/tracker/index.php?func=detail&aid=1709878&group_id=159211&atid=943471
gigamaster 
The User mailer process doesn't work !
New user don't get email to confirm registration.
Linux 2.4 - Apache 1.3.36 - MySQL 4.0.27 - PHP 4.4.3
xoops_cube_21rc_snapshot_2007325-0012
Legacy System »» Preferences »» Mail Setup
Options set to default PHP mail()
- Fail !!!
Lost Password !
- Fail !!!
Test Server:
<?php
echo "Send to self-server japan.host<br>";
mail ('xoopscube@xoopserver.com', 'TEST TITLE', 'TEST');
echo "Mail sent!";
echo "<br>Sent to Gmail account<br>";
mail ('xoops.guide@gmail.com', 'TEST TITLE', 'TEST');
echo "Mail sent!";
?>
- Ok !
Seems problem doesn't come from server config.