ARTICLE AD BOX
When your React app makes a request, the browser often sends an "OPTIONS" request first (a preflight check) to see if the server allows the actual request. If your backend has specific logic that blocks certain methods or if there's a typo in the config, the preflight fails.
Try being explicit with your configuration to ensure all bases are covered:
JavaScript
app.use(cors({ origin: 'http://localhost:3000', // Allow only your frontend methods: ['GET', 'POST', 'PUT', 'DELETE'], allowedHeaders: ['Content-Type', 'Authorization'] }));