Rasa not returning whole file in callback_url while running on different machine?

Question

I have two servers; receiving server(1) runs on NodeJS, and the sender server(2) is on Python rasa nlu.

Server(1) code :

import {Storage} from "@google-cloud/storage";
this.post("/webhook",
 async (req, res) => {
   const storage = new Storage({/** google credential filename */ });
   const clientBucket = storage.bucket(/** bucket name */);

  // Create a reference to a file object
  const fileName = `${moment().format("YYYYMMDDHHmmss")}.tar.gz`;
  const file = clientBucket.file(fileName);
  req.pipe(file.createWriteStream());
  req.on("end", () => {
    // have to update in db that file has been uploaded
  });
})

Problem: When running both servers on HTTP file uploading works fine and I received the whole file. But if any one server is on HTTPS it stops working and only gets a few chunks of data or not.