Error when i go into production with react.js

I have create an app with react.js. I wanted to go into production.

I did

npm run build

serve -s build 

I go on localhost:5000

The welcome page works very well, but when i go on localhost:5000/maini have an error

404 | The requested path could not be found

I tried to redo npm run build, but that did not work

What do you propose ?

EDIT

Package.json

{
  "name": "name-app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "firebase": "^5.10.0",
    "node-sass": "^4.11.0",
    "p5": "^0.8.0",
    "react": "^16.8.6",
    "react-dom": "^16.8.6",
    "react-p5-wrapper": "0.0.4",
    "react-router-dom": "^5.0.0",
    "react-scripts": "2.1.8",
    "socket.io-client": "^2.2.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": [
    ">0.2%",
    "not dead",
    "not ie <= 11",
    "not op_mini all"
  ],
  "description": "This project was bootstrapped with [Create React App](https://github.com/facebook/create-react-app).",
  "main": "index.js",
  "devDependencies": {},
  "author": "",
  "license": "ISC"
}

It looks like the "-s" or "--single" argument/option on the serve package is either not working or no longer working as expected so requests to paths other than "/" are not being rewritten.

Take a look at the following issue for the serve package: https://github.com/zeit/serve/issues/525

In my test setup downgrading serve as suggested in the bug report fixed the issue.

npm uninstall -g serve

npm install -g serve@10.1.1

serve -s build