会话变量不持久

我似乎无法让我的会话变量输出。它在我使用的另一个上工作得很好:

    $_SESSION['status']['register']['username'] = $username;
    header('Location: register-form.php');

当你被带到register-form.php时，它应该为你输出变量:

<?php
      if(isset($_SESSION['status']['register']['username'])){
      $username = $_SESSION['status']['register']['username'];
      } else {
      $username = '';
      }
?>

在email_address上使用完全相同的代码并且工作良好。

下面是电子邮件

$_SESSION['status']['register']['email_address'] = $email_address;

在表单页:

<?php
     if(isset($_SESSION['status']['register']['email_address'])){
     $ea_value = $_SESSION['status']['register']['email_address'];
     } else {
     $ea_value = '';
     }
?>