php include not working on host server but works on local (xampp) server

I cannot resolve why what works locally fails at the host server. It connects to the database, retrieves and displays data, but it fails to retrieve the data and include the form. Hopefully, I have included enough code.

First the data is retrieved and displayed:

/*-------------------  DISPLAY ACCESSORIES ------------------*/
if(isset($_GET['table']) && $_GET['table'] === "accessories") 
{
    $table = 'accessories';      

    include '../includes/dbconnect.php';    

    try {
        $result = $db->query("SELECT * FROM $table");

        while($row = $result->fetch(PDO::FETCH_ASSOC)){

            $accessories[] = array(
                'id' => $row['id'],
                'buy_link' => $row['buy_link'],
                'img' => $row['img'],
                'item_number' => $row['item_number'],
                'name' => $row['name'],
                'description' => $row['description'],
                'laser_series' => $row['laser_series'],
                'laser_model' => $row['laser_model'],
                'quantity' => $row['quantity'],
                'price' => $row['price'],
            );
        }
    }   
    catch (PDOException $e)
    {
       $error = 'Error fetching data.' . $e->getMessage();
       include 'error.html.php';
       exit();
    }

    try {
        $sql2 = 'DESCRIBE accessories';
        $s2= $db->prepare($sql2);
        $s2->execute();
        $table_fields = $s2->fetchAll(PDO::FETCH_COLUMN);
    }
    catch (PDOException $e)
    {
        $error = 'Error fetching data from database.';
        include 'error.html.php';
        exit();
    }

    // Close database connection
    $db = null;

    // Display data on included page
    include 'display-accessories.html.php';
    exit();
}

Then, in the row the user wishes to edit, he clicks the edit button. Here's that html:

<form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']); ?>" method="post">
    <input type="hidden" name="id" value="<?php htmlout($accessory['id']); ?>"> 
    <button class="btn btn-default btn-sm" type="submit" name="action" value="edit_accessories">Edit</button>
</form>

Clicking the edit button triggers this php, which fails (not locally). It does not include the file (the path is correct; in the same folder).

/*-------------------  EDIT ACCESSORIES ------------------*/
if(isset($_POST['action']) && $_POST['action'] === "edit_accessories") 
{
    // Assign name of table being queried to variable
    $table = 'accessories';

    // Sanitize posted data
    $id = sanitize($_POST['id']);

    // Connect to database
    include '../includes/dbconnect.php';

    try {
        $sql = "SELECT * FROM $table WHERE id = :id"; 
        $s = $db->prepare($sql);
        $s->bindValue(':id', $id);
        $s->execute();
    }
    catch (PDOException $e)
    {
        $error = 'Error fetching data.' . $e->getMessage();
        include 'error.html.php';
        exit();
    }

    // Store single row result in $item associative array
    $item = $s->fetch(PDO::FETCH_ASSOC);  

    // Close database connection
    $db = null;

    // Display row content in form
    include 'edit-accessories-form.html.php';
    exit();
}

If anyone has any ideas why this does not work, I welcome your insight!