Failed to move file to using PHPMailer

I am trying to create a form with PHPMailer that allows me to send files. Sometimes it goes well but most of the time I get the following error:

'Failed to move file to C:\Inetpub\vhosts\mywebsite.nl\tmp\4a47EC1.tmp.jpg '.

This is the code:

<?php
//Import PHPMailer classes into the global namespace
//These must be at the top of your script, not inside a function

use PHPMailer\PHPMailer\Exception;
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;

require 'phpmailer/src/Exception.php';
require 'phpmailer/src/PHPMailer.php';
require 'phpmailer/src/SMTP.php';

$msg = '';
if (array_key_exists('userfile', $_FILES)) {
    //First handle the upload
    //Don't trust provided filename - same goes for MIME types
    //See http://php.net/manual/en/features.file-upload.php#114004 for more thorough upload validation
    //Extract an extension from the provided filename
    $ext = PHPMailer::mb_pathinfo($_FILES['userfile']['name'], PATHINFO_EXTENSION);
    //Define a safe location to move the uploaded file to, preserving the extension
    $uploadfile = tempnam(sys_get_temp_dir(), hash('sha256', $_FILES['userfile']['name'])) . '.' . $ext;

    if (move_uploaded_file($_FILES['userfile']['tmp_name'], $uploadfile)) {
        //Upload handled successfully
        //Now create a message
        $mail = new PHPMailer();
        //Server settings
        //$mail->SMTPDebug = SMTP::DEBUG_SERVER;       //Enable verbose debug output
        $mail->isSMTP();                               //Send using SMTP
        $mail->Host       = 'smtp.mail.yahoo.com';     //Set the SMTP server to send through
        $mail->SMTPAuth   = true;                      //Enable SMTP authentication
        $mail->Username   = '[email protected]';       //SMTP username
        $mail->Password   = 'mypassword';              //SMTP password
        $mail->SMTPSecure = 'ssl';                     //Enable TLS encryption; `PHPMailer::ENCRYPTION_SMTPS` encouraged
        $mail->Port       = 465;                       //TCP port to connect to, use 465 for `PHPMailer::ENCRYPTION_SMTPS` above
        $mail->setFrom('[email protected]', 'First Last');
        $mail->addAddress('[email protected]', 'John Doe');
        $mail->Subject = 'PHPMailer file sender';
        $mail->Body = 'My message body';
        //Attach the uploaded file
        if (!$mail->addAttachment($uploadfile, 'My uploaded file')) {
            $msg .= 'Failed to attach file ' . $_FILES['userfile']['name'];
        }
        if (!$mail->send()) {
            $msg .= 'Mailer Error: ' . $mail->ErrorInfo;
        } 
        else {
            $msg .= 'Message sent!';
        }
    } 
    else {
        $msg .= 'Failed to move file to ' . $uploadfile;
    }
}
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>PHPMailer Upload</title>
</head>
<body>
<?php include 'inc/menu-inc.php' ?>
    <div id="wrap">
<?php if (empty($msg)) { ?>
    <form method="post" enctype="multipart/form-data">
        <input type="hidden" name="MAX_FILE_SIZE" value="100000"> Send this file: <input name="userfile" type="file">
        <input type="submit" value="Send File">
    </form>
<?php } else {
    echo htmlspecialchars($msg);
} ?>
    </div>
<?php include 'inc/footer-inc.php' ?>
</body>
</html>

Does anyone have an idea how this is possible?

Thanks in advance for responses

Solution

I have found the solution.

I have removed the hidden input line.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
    <title>PHPMailer Upload</title>
</head>
<body>
    <div id="wrap">
<?php if (empty($msg)) { ?>
    <form method="post" enctype="multipart/form-data">
        <!--<input type="hidden" name="MAX_FILE_SIZE" value="100000"> REMOVE THIS ROW -->
        Send this file: <input name="userfile" type="file">
        <input type="submit" value="Send File">
    </form>
<?php } else {
    echo htmlspecialchars($msg);
} ?>
    </div>
</body>
</html>