Requests made through pinia display 'MulterError: Unexpected field at wrappedFileFilter'

[meorionel]

There is nothing error with using html forms, but requests made through pinia will get 'MulterError: Unexpected field att wrappedFileFilter'

// Front-end(pinia)
async postCover() {
            try {
                console.log(1);
                // const post_cover = this.postCover;
                const formData = new FormData();
                formData.append('post_cover', this.cover);

                const res = await axios.post('/api/cover', formData, {
                    headers: {
                        'Content-Type': 'multipart/form-data'
                    }
                });
            } catch(error) {
                console.log(error);
            }
        }

// back-end(node.js)
const multer = require("multer");
const upload = multer({ dest: "uploads/" });

router.post("/cover", upload.single("cover"), async (req, res) => {
    console.log(1);
    res.send(req.file);
});