I used react as frontend and firebase as backend. And it succeeded in deploying to vercel.

But it just shows a blank screen.

And when I go to the console, this error code appears.

Uncaught FirebaseError: Firebase: Error (auth/invalid-api-key)

my repo: https://github.com/kagrin97/fireBase-twitter

package.json

{
  "name": "firebase-twitter",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.16.4",
    "@testing-library/react": "^13.3.0",
    "@testing-library/user-event": "^13.5.0",
    "@types/jest": "^27.5.2",
    "@types/node": "^16.11.43",
    "@types/react": "^18.0.15",
    "@types/react-dom": "^18.0.6",
    "firebase": "^9.8.4",
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "react-router-dom": "^6.3.0",
    "react-scripts": "5.0.1",
    "typescript": "^4.7.4",
    "uuid": "^8.3.2",
    "web-vitals": "^2.1.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "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"
    ]
  },
  "devDependencies": {
    "@types/uuid": "^8.3.4",
    "autoprefixer": "^10.4.7",
    "gh-pages": "^4.0.0",
    "postcss": "^8.4.14",
    "tailwindcss": "^3.1.5"
  },
  "homepage": "."
}