Thanks for your reply.
I uploaded everything, re-checked, but it is not working.
It looks like working as the page returned to thank you page, but I don't get any email.
We have another contact form, under the sub-domain, and it is working fine.
I compared each files and I don't see any difference except one, which is on "PEAR_Mail_using_SMTP_php.php_line 115".
Working one says $mailRef="WA_MailObject", not working one says $mailRef="WAUE".
I replaced the word but no luck.
I am attaching the files just in case. email passwords are replaced with xxx...