hotmail won't accept my mail()

[SN1P3R_85]

I have an email program, and have gotten it to mostly work, except that hotmail marks emails from my site as dangerous. Why is this? From what I've read, there is something wrong with my header. This is the part that needs fixing:

 

$recipient = $row['Email'];
$subject = 'lost password';
$mailbody = 'blah';

$header = "To: " . $row['Email'] . "\n";
        $header .= "From: www.caidenhome.com <[email protected]>\n";
        $header .= "MIME-Version: 1.0\n";
        $header .= "Content-type: text/html; charset=iso-8859-1\n";
        $header .= "X-Priority: 1\n";
$header .= "X-MSmail-Priority: High";

        $email_msg = mail($recipient, $subject, $mailbody, $header);