can someone tell me why i’m facing this error in php [duplicate]

<!DOCTYPE html>
<html lang="en">
<head>
<!-- head data stats here -->
<?php
include '../include files/head.php';
?>
<!-- head data ends here -->
</head>
<body>
<div class=" container">
<?php 
        if(isset($_POST["submit"])){
            $image =$_POST["image"];
            $title =$_POST["title"];
            $errors = array();

            if(empty($image) OR empty($title) ){
                array_push($errors,"all fileds are required");
            }
            require_once "../config file/config.php";   
            
            // Check if title  already exists
            $sql = "SELECT * FROM genres WHERE title = '$title'";
            $result = mysqli_query($conn, $sql);
            $rowcount = mysqli_num_rows($result);
            if ($rowcount > 0) {
                array_push($errors, "title  already exists");
            }
            if(count($errors)> 0){
                foreach($errors as $error){
                    echo"<div  class='alert alert-danger' role='alert'>$error</div>";
            }
           }else{
            $sql ="INSERT INTO genres (image,title) VALUES (?,?)";
            $stmt =mysqli_stmt_init($conn);
            $preparestmt = mysqli_stmt_prepare($stmt,$sql);
            if ($preparestmt){
                mysqli_stmt_bind_param($stmt,"ss", $image,$title);
                mysqli_stmt_execute($stmt);
                echo " <div  class='alert alert-danger' role='alert'> title and images successfully </div>";
            } else{
                die("something went wrong");
            }
              
           }
           mysqli_close($conn); 
        }

?>


    <form action="genres.php" method="post">
            <div class="form-group">
                <label for="text"> enter titile </label>
                <input type="text" class="form-control" name="title" placeholder="title">
            </div>

            <div class="form-group">
                <label for="image">Select Image:</label>
                <input type="file" class="form-control-file" name="image" id="image">
            </div>

            <div class="form-btn">
                <input type="submit" class="btn btn-primary" value="submit"name="submit">
            </div>
    </form>
</div>








<!-- head data stats here -->
<?php
include '../include files/body.php';
?>
<!-- head data ends here -->
</body>
</html>

the error

database connection sucessful
Fatal error: Uncaught Error: mysqli object is already closed in G:xampphtdocsre zerobackend uploadinggenres.php:25
 Stack trace: 
#0 G:xampphtdocsre zerobackend uploadinggenres.php(25): mysqli_query(Object(mysqli), 'SELECT * FROM g...') 
#1 {main} thrown in G:xampphtdocsre zerobackend uploadinggenres.php on line 25

as soon as i click on submit i get this error so idk why im getting this i tried everything i could to do it on how to fix the error like did i place some brackets at wrong place or something idk like no logic is working in it so im confused aff

i try everything i could to fix the issue and the code purpose is to submit that data to my xampp server which it is not doing

<?php
$hostname = "localhost";
$dbuser = "root";
$dbpassword = "";
$dbname = "re-zero";
$conn = mysqli_connect($hostname, $dbuser, $dbpassword, $dbname);
if (!$conn) {
    die("something went wrong," . mysqli_connect_error());
} else{
    echo"database connection sucessful";
}
mysqli_close($conn);
?>