why my console.log(req.body) give: {} in nodejs - node.js

Question

I want to update a post in my bdd with the new value. When i click for validate i have an empty req.body!
exports.updatePost = (req, res, next) => {
Post.update(
{
message: req.body.message,
},
{ where: { id: req.params.id } }
)
.then(() => res.status(200).json({ message: "post modifié" }))
.catch((error) => res.status(500).json({ error }));
console.log(req.body)
console.log(req.params.id)
};
As you can see i console log my req.body for check, my req.paramas.id give me the right thing. Since i have this problem i decided to check my post route and my app.js but i didn't see anything.
my route is like this:
const express = require("express");
const router = express.Router();
const postCtrl = require("../controllers/post");
const auth = require("../middleware/auth");
const multer = require("../middleware/multer-configs");
//DIFFERENTE ROUTES POUR LES POSTS, COMPRENNANTS LES DIFFERENTS MIDDLEWARE UTILES ET D'AUTHENTIFICATION
router.get("/", auth, postCtrl.getAllPost);
router.post("/", auth, multer, postCtrl.createPost);
router.delete("/:id", auth, postCtrl.deletePost);
router.put("/:id", auth, postCtrl.updatePost);
router.get("/:id", auth, postCtrl.getPostByUserId);
module.exports = router;
and my app.js is like this:
const express = require("express");
require("dotenv").config();
const helmet = require("helmet");
const cors = require("cors");
const db = require("./models");
const path = require("path");
const bodyParser = require("body-parser");
const userRoutes = require("./routes/user");
const postRoutes = require("./routes/post");
const likeRoutes = require("./routes/like");
const commentRoutes = require("./routes/comment");
const app = express();
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
//MODULE C.O.R.S
app.use(cors());
app.use(express.urlencoded({ extended: true }));
// POST
app.use("/api/post", postRoutes);
I don't really understand why my backend can't see the back or don't give me the result of my body.
my client side is like this actually:
const updatePost = () => {
if (textEdit) {
const data = new FormData();
data.append("message", textEdit);
axios.put(`http://localhost:5000/api/post/${id}`, data, {
headers: {
Authorization: `Bearer ${sessionStorage.getItem("authToken")}`,
},
})
.then((res) => {
console.log(res);
console.log(id)
console.log(message)
console.log(textEdit)
})
}
}