404 for all routes with included locale - NextJS with next-i18next - reactjs

Question

Hi I am following the docs from here: github docs
, but all URLs with locales return 404.
For the example:
localhost:3000/de/second-page = 404
localhost:3000/en/second-page = 404
localhost:3000/de = 404
localhost:3000/en = 404
same for the default locale.
localhost:3000/second-page = 200
localhost:3000 = 200
I guess, this is because there is no pages/de/second-page.js, for the example, but what's the purpose then of this library, if it doesn't solve this problem.
I have searched a lot and I know about localSubpaths, but seems that it doesn't work:
module.exports = new NextI18Next({
otherLanguages: ['fr'],
//localeSubpaths: localeSubpathVariations[localeSubpaths],
localeSubpaths: {
de: 'de',
en: 'en',
}
})
It doesn't work in my app, but it doesn't work in their sample, too: their sample

Answer 1

Have you checked these two steps ?
After creating and exporting your NextI18Next instance, you need to
take the following steps to get things working:
Create an _app.js file inside your pages directory, and wrap it with
the NextI18Next.appWithTranslation higher order component (HOC). You
can see this approach in the examples/simple/pages/_app.js. Your app
component must either extend App if it's a class component or define a
getInitialProps if it's a functional component (explanation here).
Create a next.config.js file inside your root directory if you want to
use locale subpaths. You can see this approach in the
examples/simple/next.config.js (Next.js 9.5+ required).
const { nextI18NextRewrites } = require('next-i18next/rewrites')
const localeSubpaths = {
de: 'de',
en: 'en',
};
module.exports = {
rewrites: async () => nextI18NextRewrites(localeSubpaths),
publicRuntimeConfig: {
localeSubpaths,
},
}