CORS issue in (Vercel Hosting) MERN Stack Project preflight request doesn't pass access control

Question

Access to XMLHttpRequest at 'https://hr-360.vercel.app/users/login' from origin'https://hr360.vercel.app' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

POST https://hr-360.vercel.app/users/login net::ERR_FAILED

I add following codes but error still there:

npm install cors

const cors = require('cors');

// First attempt
app.use(cors({
    origin: ["https://hr360.vercel.app"],
    methods: ["POST", "GET"],
    credentials: true
}));

// Second attempt
// Enable CORS for all routes
app.use(function(req, res, next) {
    res.header('Access-Control-Allow-Origin', '*'); // '*' allows any origin, you can restrict it to specific origins
    res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE');
    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization');
    next();
});