邮件功能在wordpress中不起作用

i have customized my WordPress using PHP and include some PHP file in WordPress has template but the mail function is not working there please help me out

$headers  = 'MIME-Version: 1.0' . "
";
$headers .= 'Content-type: text/html; charset=iso-8859-1' . "
";
mail($to, $subject, $ip, $headers);
?>

Try to use wordpress inbuilt function wp_mail()

Documentation http://codex.wordpress.org/Function_Reference/wp_mail

Then wit filters you can change "from" and "from name"

http://codex.wordpress.org/Plugin_API/Filter_Reference/wp_mail_from http://codex.wordpress.org/Plugin_API/Filter_Reference/wp_mail_from_name

if this does not work, then it is time to check server set up...