I am using Sendgrid in nodejs to send and receive emails

I am trying to maintain a thread if someone replies to an email

I tried so many solutions but no luck

here is my code for sending and receiving code:

const express = require("express");
const router = express.Router();
const sgMail = require("@sendgrid/mail");
const multer = require("multer");
const axios = require("axios");
const FormData = require("form-data");
const parse = require("parse-headers");

const upload = multer();

sgMail.setApiKey(process.env.SG_API_KEY);

// Helper function to extract `Message-ID` from headers
const getMessageIdFromHeaders = (headers) => {
  return headers['x-message-id'] || headers['message-id'];
};

// Send email with reply thread management
router.post("/send", upload.array("files", 10), async (req, res, next) => {
  const { email, text, subject, messageId, references, inReplyTo } = req.body;

  // Prepare the email message
  const msg = {
    to: email,
    from: process.env.SG_FROM_EMAIL,
    subject: subject,
    text: text,
    headers: {}
  };

  // Add reply threading headers if provided
  if (messageId) {
    //msg.replyTo = email;
    //msg.headers['Message-ID'] = `<${Date.now()}@mysite.online>`;
    msg.headers['References'] = `${references} ${messageId}`;
    msg.headers['In-Reply-To'] = `${messageId}`;

  }

  // Handle file attachments
  let attachments = [];
  
  for (let i = 0; i < req.files.length; i++) {
    attachments.push({
      content: req.files[i].buffer.toString("base64"),
      filename: `${req.files[i].originalname}`,
      type: req.files[i].mimetype,
      disposition: "attachment",
    });
  }

  if (attachments.length) msg.attachments = attachments;
  console.log(req.body);

  try {
    console.log(msg);
    const response = await sgMail.send(msg);
    console.log(response);
    const messageId = getMessageIdFromHeaders(response[0].headers);
    res.status(200).json({ referenceId: messageId });
  } catch (error) {
    console.error('Error sending email:', error);
    res.status(500).json({ error: 'Failed to send email' });
  }

  next();
});

// Webhook endpoint for handling incoming emails
router.post("/webhook", upload.any(), async (req, res, next) => {
  try {
    const body = req.body;
    const headers = parse(body.headers); 

    // Extract Message-ID from headers
    const messageId = headers['message-id'];
    const references = headers['references'];
    const inReplyTo = headers['in-reply-to'];

    const envelope = JSON.parse(body.envelope);

    const apiUrl = `${process.env.BACKEND_URL}/receive-email/${envelope.from}`;

    const formData = new FormData();
    req.files.forEach((file, index) => {
      const blob = new Blob([file.buffer]);
      formData.append("files", blob, file.originalname);
    });

    formData.append("communicationType", "email");
    formData.append("from", envelope.from);
    formData.append("body", body.text);
    formData.append("subject", body.subject);
    formData.append("messageSid", messageId); 
    formData.append("references", references); 
    formData.append("inReplyTo", inReplyTo); 

    await axios.post(apiUrl, formData, {
      headers: {
        "Content-Type": "multipart/form-data",
      },
    });

  } catch (e) {
    console.error("Error handling webhook:", e);
  }
  return res.sendStatus(200);
});

module.exports = router;