note 78163 added to ref.mail

I tried to use mail(), Pear::Mail and phpmailer to send the mail to hotmail. But all the mails are filtered into junk folder and shows "You may not know this sender." Can anyone here help me on this problem? Any suggestion is extremely welcomed. ---- Server IP: 203.202.10.60 Probable Submitter: 122.116.163.39 ---- Manual Page -- http://www.php.net/manual/en/ref.mail.php Edit -- https://master.php.net/note/edit/78163 Del: integrated -- https://master.php.net/note/delete/78163/integrated Del: useless -- https://master.php.net/note/delete/78163/useless Del: bad code -- https://master.php.net/note/delete/78163/bad+code Del: spam -- https://master.php.net/note/delete/78163/spam Del: non-english -- https://master.php.net/note/delete/78163/non-english Del: in docs -- https://master.php.net/note/delete/78163/in+docs Del: other reasons-- https://master.php.net/note/delete/78163 Reject -- https://master.php.net/note/reject/78163 Search -- https://master.php.net/manage/user-notes.php