If you are using any client-side framework like  Vue ,  Angular ,  React   and so, you are probably doing client-side routing which is letting the browser handles the routes E.g.  myapp.com/about , myapp.com/account/user etc... By default, the server only recognizes the root (/) and if you try to refresh the page (f5) or  enter directly the  URL  myapp.com/about   you will get 404 ERROR because you are sending an HTTP request to the server in the route  /about,   but your server doesn't handle routes different from (/). To solve this problem I found a really nice approach  which is a  simple fallback handler in the  Startup.cs of our .NET Core app:  public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory) { ....Your configuration app.UseMvc(routes => { routes.MapRoute( ...