php in javascript. the server responded with a status of 404 (Not Found) [duplicate]

I just started to learn js, I ran into a problem. I have a feedback form on my landing page. I need the emails to come to gmail. For this I wrote one js script which links to a php file using fetch. however I get an error in the console. and of course it doesn’t send the request

html

 <form action="#" autocomplete="on" method="POST" class="form-action" id="form" enctype="multipart/form-data">
                    <h3 class="h3-form">Let's jump onto message</h3>
                    <input class="form-input _req" type="text" name="Name" placeholder="Name">
                    <input class="form-input _req _email" type="text" name="Email" placeholder="Email">
                    <textarea class="form-input _req" cols="30" rows="1" style="resize: none;" name="Message" placeholder="Your idea"></textarea>
                    <div class="attaching">
                        <div class="form-file-preview" id="formPreview"></div>
                        <label class="attach-label">
                            <input id="formFile" type="file" accept=".pdf,.doc,.docx,.jpeg,.xls,.xlsx,.jpg,.csv,.ods,.tsv" multiple data-max-size="10485760" name="file" class="hiddenInput" data-hj-allow="true">
                            <span class="icon-paperclip">
                                <img src="/img/attach.svg" alt="">
                            </span>
                            <div class="attach">Attach Files
                            </div>
                        </label>
                    </div>
                    <button class="send" type="submit">Send</button>
                </form>

JS

const form = document.getElementById('form');
const sendmessage = document.getElementById('sendmessage');
form.addEventListener('submit', formSend);

async function formSend(e) {
    e.preventDefault();
    let error = formValidate(form);
    let formData = new FormData(form);
    formData.append('file', formFile.files[0]);
    if (error === 0) {
        sendmessage.classList.add('_sending');
        let response = await fetch('sendmail.php', {   \here is a problem
            method: 'POST',
            body: formData
        });
        if (response.ok) {
            let result = await response.json();
            alert(result.message);
            formPreview.innerHTML = '';
            form.reset();
            sendmessage.classList.remove('_sending');
        } else {
            alert("Fail");
            sendmessage.classList.remove('_sending');
        }
    }
}

function formValidate(form) {
    let error = 0;
    let formReq = document.querySelectorAll('._req');
    for (let index = 0; index < formReq.length; index++) {
        const input = formReq[index];
        formRemoveError(input);
        if (input.classList.contains('_email')) {
            if (emailTest(input)) {
                formAddError(input);
                error++;
            }
        } else {
            if (input.value === '') {
                formAddError(input);
                error++;
            }
        }
    }
    return error;

}

sendmail.php

<?php
use PHPMailerPHPMailerPHPMailer;
use PHPMailerPHPMailerException;

require 'PHPMailer/src/Exeption.php';
require 'PHPMailer/src/PHPMailer.php';

$mail = new PHPMailer(true);
$mail->CharSet = 'UTF-8';

$mail->setLanguage('en', 'phpmailer/language/');
$mail->IsHTML(true);

$mail->setFrom('[email protected]');
$mail->addAdress('[email protected]');
$mail->Subject = 'New Message';

$body = '<h1>Message on Site</h1>';
if(trim(!empty($_POST['Name']))){
  $body.='<p><strong>Name:</strong> '.$_POST['Name'].'</p>';
}
if(trim(!empty($_POST['Email']))){
  $body.='<p><strong>Email:</strong> '.$_POST['Email'].'</p>';
}
if(trim(!empty($_POST['Message']))){
  $body.='<p><strong>Message:</strong> '.$_POST['Message'].'</p>';
}

if(!empty($_FILES['file']['tmp_name'])){
$filePath = __DIR__ . "/files/" . $_FILES['file']['name'];
if (copy($_FILES['file']['tmp_name'], $filePAth)) {
  $fileAttach = $filePath;
  $body.='<p><strong>File attached</strong>';
  $mail->addAttachment($fileAttach); 
}
}
$mail->Body = $body;

if(!$mail->sent()) {
  $message = 'Error';
}else {
  $message = "Successfully";
}

$response = ['message' => $message];

header('Content-type: application/json');
echo json_encode($response);
?>

Console error:

POST 192.168.88.21:3000/sendmail.php 404 (Not Found).
_refers to script.js:51

enter image description here

enter image description here

How do I run this file so there are no errors?