我已经编写了一个代码，用于在用户查看该页面时或简单地说，在加载该页面时，使用会话变量和代码向用户发送邮件。该代码没有任何问题或错误，但指定用户根本没有收到邮件。请帮帮我。！
code.php
<?php
session_start();
$to = " '". $_SESSION['email'] ."' ";
$subject = 'Your vault number';
$message = "Your vault number is '". $_SESSION['vault_no'] ."' ";
$headers = 'From: innovation@miisky.com' . "'r'n" .
'Reply-To: innovation@miisky.com' . "'r'n" .
'X-Mailer: PHP/' . phpversion();
mail($to, $subject, $message, $headers);
?>
<?php
if(!isset($_SESSION['fullname'])){
header("Location: signin.php");}
?>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="http://maps.google.com/maps/api/js?sensor=true"></script>
<title>MiiSky | Dashboard</title>
<link href="css/bootstrap.min.css" rel="stylesheet">
<link href="font-awesome/css/font-awesome.css" rel="stylesheet">
<!-- Toastr style -->
<link href="css/plugins/toastr/toastr.min.css" rel="stylesheet">
<!-- Gritter -->
<link href="js/plugins/gritter/jquery.gritter.css" rel="stylesheet">
<link href="css/animate.css" rel="stylesheet">
<link href="css/style.css" rel="stylesheet">
<style>
</style>
</head>
<body class="body-ani">
<div id="wrapper">
<nav class="navbar-default navbar-static-side" role="navigation">
<div class="sidebar-collapse">
<ul class="nav metismenu" id="side-menu">
<li class="nav-header">
<div class="dropdown profile-element">
<a data-toggle="dropdown" class="dropdown-toggle" href="#">
<span class="clear"> <h2><span class="block m-t-xs">Hi! <strong class="font-bold"><?php
if(isset($_SESSION['fullname'])){
echo $_SESSION['fullname'];
}
?>
</strong>
</span></h2>
</div>
<div class="logo-element">
MiiSky
</div>
</li>
<li class="active">
<a href="#"><i class="fa fa-user"></i> <span class="nav-label"> Vault number? </span><span class="fa arrow" ></span></a>
<ul class="nav nav-second-level collapse">
<li>
<a><i class="fa fa-edit"></i> <span class="nav-label">Vault number is your unique number.</span></a></li>
<li>
<a><i class="fa fa-edit"></i> <span class="nav-label">Vault number is important while storing your information!</span></a></li>
<li>
<a><i class="fa fa-edit"></i> <span class="nav-label">This can be used like your key to unlock your stored information!</span></a></li>
<li>
<a><i class="fa fa-edit"></i> <span class="nav-label">Overall vault number is vital to move further!</span></a></li>
</ul>
</ul>
</div>
</nav>
<div id="page-wrapper" class="gray-bg dashbard-1">
<div class="row border-bottom">
<nav class="navbar navbar-static-top" role="navigation" style="margin-bottom: 0">
<div class="navbar-header">
<a class="navbar-minimalize minimalize-styl-2 btn btn-primary " href="#"><i class="fa fa-bars"></i> </a>
<form role="search" class="navbar-form-custom" action="search_results.html">
<div class="form-group">
<input type="text" class="form-control" name="top-search" id="top-search">
</div>
</form>
</div>
<ul class="nav navbar-top-links navbar-right">
<li>
<span class="m-r-sm text-muted welcome-message">Welcome to MiiSky</span>
</li>
<li class="dropdown">
<li>
<a href="sign_out.php">
<i class="fa fa-sign-out"></i>Lets create your profile!
</a>
</li>
<!--<li>
<a class="right-sidebar-toggle">
<i class="fa fa-tasks"></i>
</a>
</li>-->
</ul>
</nav>
<br><div style="font-size:30px; text-align:center;">
<p>Please click <a class="hvr-bounce-in" href="download.php" style="text-decoration:none;"><i>here</i></a> and get your vault number now..!!</p>
</div>
<div>
<h2 style="font-size:30px; text-align:center;">Your current address and location</h2>
<div id="map"></div>
<p style="font-size:15px; text-align:center;"><span id="address"></span></p>
<p id="error"></p>
<br>
</div>
</div>
</div>
</div>
</div>
</body>
</html>
在上面提到的代码中，邮寄部分位于顶部，具体如下代码所示！
mail.php
<?php
session_start();
$to = " '". $_SESSION['email'] ."' ";
$subject = 'Your vault number';
$message = "Your vault number is '". $_SESSION['vault_no'] ."' ";
$headers = 'From: innovation@miisky.com' . "'r'n" .
'Reply-To: innovation@miisky.com' . "'r'n" .
'X-Mailer: PHP/' . phpversion();
mail($to, $subject, $message, $headers);
?>
我认为您不需要在to地址周围加引号。
将其替换为$to=$_SESSION['email']；
然后按照建议检查你的电子邮件日志（如果你有一个邮件程序在运行）。还可以尝试使用PHP邮件从一个简单的脚本向该用户发送电子邮件——它会发送吗？这可能是你最好的选择，因为你可以看到这是你的标题还是一般的标题。
还要检查用户上的垃圾邮件文件夹，以防它被标记为垃圾邮件。
如果您从未成功地从服务器发送代码（使用复制/粘贴代码），请确保您的web主机允许发送电子邮件。
许多/大多数免费的，甚至一些付费的都禁用了它。