POST https://waste-alert-api.herokuapp.com/datas 500 (Internal Server Error)

I have created a React Project where I want to upload an Image with some data. Every method works fine except the post method. For better understanding, I added React JS part as well as Node Js code.

Node Js server works fine when I tested with POSTMAN.

React JS

const submitPostHandler = async (data) => {
    try {
      const response = await fetch(
        "https://waste-alert-api.herokuapp.com/datas",
        {
          method: "POST",
          body: data,
          headers: {
            "Content-Type": "multipart/form-data",
            Authorization: token,
          },
        }
      );

      console.log(response);
    } catch (err) {
      console.log(err);
    }
  };

    const metaData = {
      "wasteType": enteredWasteType,
      "location": {
        "lat": enteredLat,
        "long": enteredLong,
      },
    };
    console.log(metaData);

    const data = new FormData();
    data.append("image", file);
    data.append("data", metaData);

    props.submitPostHandler(data);

Node Js

router.post(
  "/datas",
  auth,
  uploadOptions.single("image"),
  async (req, res, next) => {
    const file = req.file;
    if (!file) return res.status(400).send("No image in the request");

    const fileName = file.filename;
    const basePath = `${req.protocol}://${req.get("host")}/uploads/`;
    console.log(req.body.data);
    const newData = JSON.parse(req.body.data);
const data = new Data({
      wasteType: newData.wasteType,
      location: newData.location,
      image: `${basePath}${fileName}`,
      owner: req.user._id,
    });

    try {
      await data.save();
      res.status(201).send(data);
    } catch (e) {
      res.send({ e, error: "something is wrong" });
    }
  }
);