User discovery project with github api?

I'm developing a project to find users by username using github api but when i type the username i can't get any result. my project aims to fetch the user information of the searched user from github. I can't find the error I've tried everything.

My codes:

import React,{useState, useEffect} from "react";
import { BiUser } from 'react-icons/bi';
import './App.css';


function App() {
  const [name, setName] = useState("")
  const [userName, setUserName] = useState("")
  const [followers, setFollowers] = useState("")
  const [following, setFollowing] = useState("")
  const [repos, setRepos] = useState("")
  const [avatar, setAvatar] = useState("")
  const [userInput, setUserInput] = useState("")
  const [error, setError] = useState(null)

  useEffect(()=> {
    fetch("https://api.github.com/users/example")
    .then(res => res.json())
    .then(data => {
      setData(data)
    })
  }, [])
  const setData = ({name, login, followers, following, public_repos, avatar_url}) => {
    setName(name);
    setUserName(login);
    setFollowers(followers);
    setFollowing(following);
    setRepos(public_repos);
    setAvatar(avatar_url)
  }
  const handleSearch = (e) => {
    setUserInput(e.target.value)
  }
  const handleSubmit = () => {
    fetch(`https://api.github.com/users/${userInput}`)
    .then(res => res.json())
    .then(data => {
      setData(data);
    })
  }

  return (
    <div>
      <div className="navbar">
        Github Search
      </div>
      <div className="search">
        <form onSubmit={handleSubmit}>
          <input placeholder="Github user" name="github user" onChange={handleSearch}></input>
          <button>Search</button>
        </form>
      </div>
      <div className="card">
        <div className="card-alt">
          <div className="image">
            <img src={avatar} alt="img" width="270px" height="270px"/>
          </div>
          <div className="card-content">
            <h3> {name}</h3>
            <h3>{userName}</h3>
          </div>
          <div className="card-content">
            <a> 
              <BiUser className="icon"/> 
              {followers} Followers
            </a>
          </div>
          <div className="card-content">
            <a> 
              <BiUser className="icon"/> 
              {repos} Repos
            </a>
          </div>
          <div className="card-content end">
            <a> 
              <BiUser className="icon"/> 
              {following} Following
            </a>
          </div>
        
        </div>
      </div>
    </div>
  );
}

export default App;

package.json:

{
  "name": "my-app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.16.4",
    "@testing-library/react": "^13.2.0",
    "@testing-library/user-event": "^13.5.0",
    "react": "^18.1.0",
    "react-dom": "^18.1.0",
    "react-scripts": "5.0.1",
    "web-vitals": "^2.1.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}

Where is it wrong?

Is there a problem with fetch api?

can you help me