I am using as an environment, a Cloud9.io ubuntu VM Online IDE and I have reduced by troubleshooting this error to just running the app with Webpack dev server.
I l
Hello React Developers,
Instead of doing this
disableHostCheck: true,
in webpackDevServer.config.js. You can easily solve 'invalid host headers' error by adding a .env file to you project, add the variables HOST=0.0.0.0 and DANGEROUSLY_DISABLE_HOST_CHECK=true in .env file. If you want to make changes in webpackDevServer.config.js, you need to extract the react-scripts by using 'npm run eject' which is not recommended to do it. So the better solution is adding above mentioned variables in .env file of your project.
Happy Coding :)