Error Cannot set headers after they are sent to the client - reactjs

Question

I got this error whenever I try to log In using Google Login API
In my console I get this error:
Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent
to the client
and in the screen I get white page with this error:
InternalOAuthError: Failed to fetch user profile
I'm using two Login method, one is normal and one using Passport JS
Login.jsx Login Page
import { useEffect, useContext, useRef } from "react";
import { Context } from "../../context/Context";
import axios from "axios";
import { useState } from "react"
export default function Login() {
const userRef = useRef();
const passwordRef = useRef();
const { dispatch, isFetching } = useContext(Context);
const [error, setError] = useState(false);
// FOR LOGIN
const handleSubmit = async (e) => {
e.preventDefault();
dispatch({ type: "LOGIN_START" });
try {
const res = await axios.post("/login", {
email: userRef.current.value,
password: passwordRef.current.value,
});
dispatch({ type: "LOGIN_SUCCESS", payload: res.data });
} catch (err) {
dispatch({ type: "LOGIN_FAILURE" });
setError(true)
}
};
// FOR GOOGLE LOGIN
useEffect(() => {
fetch(`http://localhost:4000/login/success`, {
method: 'GET',
credentials: 'include',
headers: {
Accept: 'application/json',
'Content-Type': 'application/json',
'Access-Control-Allow-Credentials': true,
},
})
.then((response) => {
dispatch({ type: "LOGIN_START" });
if (response.status === 200) return response.json();
throw new Error('failed to authenticate user');
})
.then((responseJson) => {
dispatch({ type: "LOGIN_SUCCESS", payload: responseJson.data });
})
.catch((error) => {
dispatch({ type: "LOGIN_FAILURE" });
// eslint-disable-next-line no-console
console.error("Failed to authenticate user", error)
});
}, []);
const google = () => {
window.open("http://localhost:4000/auth/google/callback", "_self");
};
return()
}
auth.js Route:
router.get("/login/success", (req, res) => {
if (req.user) {
res.status(200).json({
error: false,
message: "succesfull",
user: req.user,
cookies: req.cookies
});
} else {
res.status(403).json({ error: true, message: "Not Authorized" });
}
});