Cannot post Token from Client - node.js

Question

Frontend Code
<script>
const formDOM = document.querySelector(".form");
const btnSubmitDOM = document.querySelector(".btn-submit");
// get token form server
formDOM.addEventListener("submit", async (e) => {
e.preventDefault();
const email = document.querySelector("#email").value;
const password = document.querySelector("#password").value;
try {
const { data } = await axios.post(
"http://localhost:3000/api/v1/auth/login",
{ email, password }
);
console.log("token", data.token);
localStorage.setItem("token", data.token);
} catch (error) {
console.log(error);
}
});
// after submit, if authenticated, goes to protective route
btnSubmitDOM.addEventListener("click", async () => {
const token = localStorage.getItem("token");
console.log("toekn when press", token);
try {
const { data } = await axios.get("http://localhost:3000/api/v1/inventories", {
headers: {
Authorization: `Bearer ${token}`,
},
});
location.assign("/inventories");
} catch (error) {
localStorage.removeItem("token");
console.log(error);
}
});
</script>
Here is the backend code
const jwt = require("jsonwebtoken");
const auth = async (req, res, next) => {
const authHeader = req.headers.authorization;
if (!authHeader || !authHeader.startsWith("Bearer")) {
res.send("Auth route - Unauthenticated Error");
}
const token = authHeader.split(" ")[1];
console.log("token is ", token);
try {
const payload = jwt.verify(token, 'secret');
// console.log(payload);
// attached to the inventories route
req.user = {
userId: payload.userId,
email: payload.email,
};
// console.log(req.user)
next();
} catch (error) {
console.log(error);
}
};
module.exports = auth;
Here is the error from server side
token is eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1c2VySWQiOiI2MzY4ZjFiM2U1ODJlYmQ1MjJkODI4MGEiLCJlbWFpbCI6Imt5YXdAZ21haWwuY29tIiwiaWF0IjoxNjY3ODI3NzIzLCJleHAiOjE2NzA0MTk3MjN9.rptgRrYB4TrLQCxbB18JqMHd05LSox-LQuiLJS0L2Gw
/Users/kyawmyo/Desktop/software-development/nodejs-&-vanilajs-projects/inventories/middleware/authentication.js:8
const token = authHeader.split(" ")[1];
^
TypeError: Cannot read properties of undefined (reading 'split')
I try to test with postman, all working fine.
But I send request from client side, it is error, I cannot figure it out. Please help.