当我尝试使用注册功能并且我不确定为什么它给我这个错误时会发生此错误。我去过它引用的页面，我仍然不确定如何我可以纠正我使用的代码..即时通讯爸爸托管服务器如果有帮助或是错误的一部分谢谢：D
警告：mail（）[function.mail]：SMTP服务器响应：451请参阅 http://pobox.com/~djb/docs/smtplf.html。在第101行的D：\ Hosting \ 12090176 \ html \ flashrevise \ signup.php
$u = preg_replace('#[^a-z0-9]#i', '', $_POST['u']);
$e = mysqli_real_escape_string($db_conx, $_POST['e']);
$p = $_POST['p'];
$g = preg_replace('#[^a-z]#', '', $_POST['g']);
$c = preg_replace('#[^a-z ]#i', '', $_POST['c']);
$to = "$e";
$from = "auto_responder@flashrevise.co.uk";
$subject = 'Flash Revise Account Activation';
$message = '<!DOCTYPE html><html><head><meta charset="UTF-8"><title>Flash Revise Message</title></head><body style="margin:0px;
font-family:Tahoma, Geneva, sans-serif;"><div style="padding:15px; background:#333; font-size:24px; color:#CCC;"><a href="http://www.flashrevise.co.uk">
<img src="http://localhost:8101/Tutorials/sandbox/myfiles/FlashRevise/style/images/logo_white.png" width="36" height="30" at="Flash Revise" style="boder:none; float:left;"></a>
Flash Revise Account Activation </div><div style="padding:24px" font-size:17px;"> Hello '.$u.',<br><br> Click the link below to activate your account<br><br>
<a href="http://localhost:8101/Tutorials/sandbox/myfiles/FlashRevise/activation.php?id='.$uid.'&u='.$u.'&e='.$e.'&p='.$p_hash.'"> Click here to activate your account now</a><br>
<br> Login after successful activation using: <br>* Email Address:<b> '.$e.'</b><br>* Password: <b> '.$p.'</b></div></body></html>';
$headers = "From: $from\n";
$headers .= "MIME-VERSION 1.0\n";
$headers .= "Content-type: text/html; charset=iso-8859-1\n";
mail($to, $subject, $message, $headers);