使用本地主机作为服务器时，在php中通过电子邮件确认注册

我是php和web开发的新手。我正在尝试通过在用户的电子邮件上发送确认消息来确认用户的注册电子邮件。但它不起作用，是我使用localhost作为服务器的问题还是其他问题？这是我的代码

 {
   $to = $_POST['email'];
 $com_code = md5(uniqid(rand()));
   $subject = "Confirmation from OnlineShopping to $_POST['username']";
   $header = "OnlineShopping: Confirmation from OnlineShopping";
   $message = "Please click the link below to verify and activate your account. rn";
   $message .= "http://www.yourname.com/confirm.php?passkey=$com_code";
   $sentmail = mail($to,$subject,$message,$header);
   if($sentmail)
            {
   echo "Your Confirmation link Has Been Sent To Your Email Address.";
   }
   else
         {
    echo "Cannot send Confirmation link to your e-mail address";
   }
  }  

我的if（$sentmail）条件即将实现，我收到消息，您的确认链接已发送到您的电子邮件地址，但我的收件箱中没有收到任何电子邮件