How can I develop multi language ReactJS App

Question

I'm trying to build website using reactJS and headless CMS Wordpress.

Here is my App.js code:

        <Switch>
          <Route exact path="/:lng" component={Home} />
          <Route path="/:lng/About" component={About} />
          <Route path="/:lng/Projects" component={AllProjects} />
          <Route path="/:lng/Services" component={Services} />
          <Route path="/:lng/Project/:slug" component={Project} />
          <Route
            path="/:lng/service/:slug"
            component={ServiceConstructionDetails}
          />
          <Route path="/:lng/contactus" component={Contactus} />
          <Route path="/:lng/careers" component={Careers} />
          <Route path="/:lng/media" component={Media} />
          <Route path="/:lng/floor-plans/:slug" component={FloorPlans} />
          <Route path="/:lng/album/:slug" component={InnerMedia} />
        </Switch>

When running npm run build the production version is not working, I'm using react-snap to generate static pages also its not working I'm getting errors:

console.log at /: Failed to load resource: net::ERR_FAILED

I'm new to reactJS please anyone can help.

Thanks, B