When i launch the app on the web (‘‘local host’’), it gives me the error bellow:
i have the same issue
One of the packages appears to be trying to use open ssl stuff that is no longer supported as of v3, details in this article here https://roytuts.com/how-to-fix-err_ossl_evp_unsupported-in-react-js-application/
You probably just need to update your packages. I updated all the packages as I was doing the course, so you can see a working package.json here to compare https://raw.githubusercontent.com/delboy1978uk/react-native-course/master/package.json