React 和 Node 部署问题 - 部署成功但不显示前端部分

Question

我正在使用 Heroku 部署一个 React 和 Node js 网站。 Heroku 说部署成功但没有在屏幕上显示前端部分。 （显示图标）

这是我在控制台中得到的错误。当我在 mi pc 中使用客户端运行 npm start 时，它可以工作，但不能在服务器上运行。 在heroku中不显示前端所以我不知道服务器怎么样

react-dom.production.min.js:216 Error: Minified React error #321; visit https://reactjs.org/docs/error-decoder.html?invariant=321 for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
    at b (react.production.min.js:18)
    at t.useMemo (react.production.min.js:23)
    at r (I18nextProvider.js:7)
    at In (react-dom.production.min.js:157)
    at Ys (react-dom.production.min.js:267)
    at ua (react-dom.production.min.js:250)
    at la (react-dom.production.min.js:250)
    at ia (react-dom.production.min.js:250)
    at _r (react-dom.production.min.js:243)
    at Hr (react-dom.production.min.js:237)
react-dom.production.min.js:260 Uncaught Error: Minified React error #321; visit https://reactjs.org/docs/error-decoder.html?invariant=321 for the full message or use the non-minified dev environment for full errors and additional helpful warnings.
    at b (react.production.min.js:18)
    at t.useMemo (react.production.min.js:23)
    at r (I18nextProvider.js:7)
    at In (react-dom.production.min.js:157)
    at Ys (react-dom.production.min.js:267)
    at ua (react-dom.production.min.js:250)
    at la (react-dom.production.min.js:250)
    at ia (react-dom.production.min.js:250)
    at _r (react-dom.production.min.js:243)
    at Hr (react-dom.production.min.js:237)

这里有来自服务器的包 json：

{
  "name": "uep",
  "version": "1.0.0",
  "description": "",
  "main": "prueba.js",
  "engines": {
    "node": "v14.15.1"
  },
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "node app.js",
    "build": "cd client && npm install && npm run build",
    "server": "nodemon index.js --ignore client"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "nodemon": "^2.0.7"
  },
  "dependencies": {
    "body-parser": "^1.19.0",
    "cors": "^2.8.5",
    "dotenv": "^8.2.0",
    "express": "^4.17.1",
    "express-fileupload": "^1.2.1",
    "heroku": "^7.52.0",
    "mongod": "^2.0.0",
    "mongodb": "^3.6.3",
    "mongoose": "^5.11.14",
    "multer": "^1.4.2",
    "nodemailer": "^6.5.0",
    "react": "^17.0.2",
    "react-dom": "^17.0.2"
  }
}

这里有来自客户端的 package.json

{
  "proxy": "http://localhost:3001/",
  "name": "uep-page",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "axios": "^0.21.1",
    "bootstrap": "^4.6.0",
    "emailjs-com": "^2.6.4",
    "i": "^0.3.6",
    "i18next": "^20.1.0",
    "react": "^17.0.1",
    "react-bootstrap": "^1.5.1",
    "react-classes": "^1.1.1",
    "react-hook-form": "^7.1.0",
    "react-i18next": "^11.8.11",
    "react-pdf": "^5.2.0",
    "react-router": "^5.2.0",
    "react-router-dom": "^5.2.0",
    "react-router-hash-link": "^2.4.0",
    "react-scripts": "1.1.5",
    "react-scroll": "^1.8.2"
  },
  "scripts": {
    "predeploy": "npm run build",
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  },
  "devDependencies": {
    "gh-pages": "^3.1.0",
    "prettier": "2.2.1"
  }
}