安装React时出现Npm启动问题，如何解决？

在安装了node和全局create-react-app之后，我使用'npm install -g create-react-app'创建了我的第一个应用程序，然后我使用'npx（或npm，两者都尝试过）create-react-app appname'开始创建应用程序，成功创建了应用程序，直到我在'appname'目录中执行'npm start'时出现以下错误。
E:\Sang\React\myapp>npm start

myapp@0.1.0 start E:\Sang\React\myapp
react-scripts-start

'react-scripts-start'不被识别为内部或外部命令，可执行程序或批处理文件。
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! myapp@0.1.0 start: react-scripts-start
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the myapp@0.1.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
npm ERR! A complete log of this run can be found in:
npm ERR! C:\Users\Sang Tonsing\AppData\Roaming\npm-cache_logs\2020-09-03T12_06_34_133Z-debug.log
这是我在package.json中的脚本代码

{
"name": "myfirstreact",
"version": "0.1.0",
"private": true,
"dependencies": {
"@testing-library/jest-dom": "^4.2.4",
"@testing-library/react": "^9.5.0",
"@testing-library/user-event": "^7.2.1",
"react": "^16.13.1",
"react-dom": "^16.13.1",
"react-scripts": "3.4.3"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts 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"
]
}
}

请帮我解决问题，我计划使用react构建自己的网站。非常感谢您。