Trying to post a formData using axios.post but getting `Unsupported Media type` error

I am trying to send a post request to a spring boot server via axios.post.
Here is my code snippet

export function createSingleProduct(productData) {
  const formData = new FormData();
  const data = {
    catergoryName: productData[0].product.categoryName,
    productName: productData[0].product.productName,
    serialNumber: productData[0].product.serialNumber,
    purchasePrice: parseInt(productData[0].product.purchasePrice),
    purchaseDate: productData[0].product.purchaseDate,
    warrantyInYears: parseInt(productData[0].product.warrantyInYears),
    warrantyExpiryDate: productData[0].product.warrantyExpiryDate,
  };

  formData.append("product", data);
  formData.append("productPhoto", productData[0].productPhoto);

  const config = {
    headers: {
      apiKey: api_key,
      "Content-Type": "multipart/form-data",
    },

  };
  console.log(config.headers);

  return axios.post(`${API_BASE_URL}/products`, formData, config.headers);
}

I have specified the content type but still I am getting the below error:

{
    "timestamp": "05-20-2023 01:27:36",
    "status": 415,
    "error": "Unsupported Media Type",
    "message": "Content type 'application/octet-stream' not supported",
    "path": "/product-crud/products"
}

The backend is okay. I have checked with Postman. Anyone can help me?