Netlify deploy issue on build

site link - https://react-chat-page.netlify.app/

github - https://github.com/mrshawnhum/chat-app

I have recently added a redirect file to fix a bug when you refresh the site and I added automatic deploys with netlify-cli to my project. The first time I added Yarn Run Build and received an exit code 127 when attempting to deploy. I manually changed it on netlify to Yarn Build and still receive the same message. I also attempted to clear the cache and manually deploy the site and still receive the same message.

  "name": "client",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^4.2.4",
    "@testing-library/react": "^9.3.2",
    "@testing-library/user-event": "^7.1.2",
    "font-awesome": "^4.7.0",
    "netlify-cli": "^2.58.0",
    "query-string": "^6.13.1",
    "react": "^16.13.1",
    "react-dom": "^16.13.1",
    "react-emoji": "^0.5.0",
    "react-router": "^5.2.0",
    "react-router-dom": "^5.2.0",
    "react-scripts": "3.4.1",
    "react-scroll-to-bottom": "^3.0.0",
    "socket.io-client": "^2.3.0"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "postbuild": "cp_redirects ./build/",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  }
}