Failed Deploy to VERCEL: Error 404

I need help Mr Basir:

I get an error 404 when i deploy to VERCEL.

The 3 routes: Home, Cart and SignIn seems to work but no product, users. And connection to the database failed, i suspect. But it was working fine when i test it locally in my dev environment.

I NEED HELP, im stuck here.

My repo: https://github.com/juanchoancap/amazona

My Failed App: https://mern-amazona-dythc97es-juanchoancap.vercel.app/