Asp.net core HttpsRedirectionMiddleware Failed to determine the https port for redirect

See the documentation for various ways of configuring a non-default HTTPS port.

Which approach suits your scenario best depends on how your application is set up and hosted. You could for example add a setting:

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
        .UseSetting("https_port", "5001")
        .UseStartup<Startup>();