Why is Asp.Net Core Kestrel server returns 404 to Ngrok and Controller is never gets called?

Question

For several days I am trying to run a simple asp.net core application, with setup webhook for Telegram bot. It runs on Mac, with Kestrel server, and Ngrok over it for proxying https to webhook. Currently it returns 404 to Ngrok and also I see 404 in console. Any help is appreciated. I have tried various modifications of this line ./ngrok http http://localhost:5000 -host-header=localhost:5000

I am a very beginner in Asp.Net Core. Here is my core parts of app:

[Route("/")]
[ApiController]
public class UpdateController : ControllerBase
{
    [HttpPost]
    public async Task<OkResult> Post([FromBody]Update update)

This one is never gets called. Here is my Program.cs

public class Program
{
    public static void Main(string[] args)
    {
        BuildWebHost(args).Run();
    }

    private static IWebHost BuildWebHost(string[] args) =>
        WebHost.CreateDefaultBuilder(args)
            .UseKestrel()
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseStartup<Startup>()
            .Build();
}

Startup.cs

public class Startup
{
    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        
        Bot.GetBotClientAsync().Wait();
    }
}

Bot.cs

public static class Bot
{
    private static TelegramBotClient botClient;
    private static List<Command> commandsList;

    public static IReadOnlyList<Command> Commands => commandsList.AsReadOnly();

    public static async Task<TelegramBotClient> GetBotClientAsync()
    {
        if (botClient != null)
        {
            return botClient;
        }

        commandsList = new List<Command>
        {
            new StartCommand()
        };

        botClient = new TelegramBotClient(AppSettings.Token);
        await botClient.SetWebhookAsync(AppSettings.NGrokUrl);
        return botClient;
    }
}

Setting the webhook works fine, Ngrok receives requests, but the answer from Kestrel is always 404, and Post method is never get called.

An example of an output in console:

dbug: Microsoft.AspNetCore.Hosting.Diagnostics[3]
      Hosting starting
dbug: Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServer[2]
      Failed to locate the development https certificate at '(null)'.
dbug: Microsoft.AspNetCore.Hosting.Diagnostics[4]
      Hosting started
dbug: Microsoft.AspNetCore.Hosting.Diagnostics[0]
      Loaded hosting startup assembly eBot
Hosting environment: Development
Content root path: /Users/yuriibabii/Projects/eBot/eBot
Now listening on: http://localhost:5000
Application started. Press Ctrl+C to shut down.
dbug: Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets[6]
      Connection id "0HM4GMVPJLPSF" received FIN.
dbug: Microsoft.AspNetCore.Server.Kestrel[39]
      Connection id "0HM4GMVPJLPSF" accepted.
dbug: Microsoft.AspNetCore.Server.Kestrel[1]
      Connection id "0HM4GMVPJLPSF" started.
dbug: Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets[7]
      Connection id "0HM4GMVPJLPSF" sending FIN because: "The client closed the connection."
dbug: Microsoft.AspNetCore.Server.Kestrel[10]
      Connection id "0HM4GMVPJLPSF" disconnecting.
dbug: Microsoft.AspNetCore.Server.Kestrel[2]
      Connection id "0HM4GMVPJLPSF" stopped.
dbug: Microsoft.AspNetCore.Server.Kestrel[39]
      Connection id "0HM4GMVPJLPSG" accepted.
dbug: Microsoft.AspNetCore.Server.Kestrel[1]
      Connection id "0HM4GMVPJLPSG" started.
dbug: Microsoft.AspNetCore.Server.Kestrel[39]
      Connection id "0HM4GMVPJLPSH" accepted.
dbug: Microsoft.AspNetCore.Server.Kestrel[1]
      Connection id "0HM4GMVPJLPSH" started.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
dbug: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[0]
      Wildcard detected, all requests with hosts will be allowed.
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 45.4537ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000001": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000001": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 GET http://localhost:5000/  
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSG" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 9.3331ms 404 
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 10.7676ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000002": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000002": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 8.5738ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000003": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000003": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 8.8111ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000004": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000004": done reading request body.
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 POST http://localhost:5000/ application/json 375
trce: Microsoft.AspNetCore.HostFiltering.HostFilteringMiddleware[2]
      All hosts are allowed.
dbug: Microsoft.AspNetCore.Server.Kestrel[9]
      Connection id "0HM4GMVPJLPSH" completed keep alive response.
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 9.6591ms 404 
dbug: Microsoft.AspNetCore.Server.Kestrel[25]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000005": started reading request body.
dbug: Microsoft.AspNetCore.Server.Kestrel[26]
      Connection id "0HM4GMVPJLPSH", Request id "0HM4GMVPJLPSH:00000005": done reading request body.

Answer 1

Have you post all your Startup class? I don't see any ConfigureServices method where you have to have the services.AddMvc().AddMvcOptions() line, nor the app.UseMvc() line in the Configure method.

I'm not so sure, but I always thought you need this two lines to enable controllers.

Try to change your Startup class in this way:

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().AddMvcOptions();
        services.AddControllersWithViews();
    }


    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        
        app.UseRouting();
        app.UseMvc();

        Bot.GetBotClientAsync().Wait();
    }
}

Answer 2

With some modifications to @PiGi78 answer, it did work. Here is the final solution:

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc().AddMvcOptions(ApplyMvcOptions);
        services.AddControllersWithViews();
        services.AddControllers().AddNewtonsoftJson();
    }

    private void ApplyMvcOptions(MvcOptions options)
    {
        options.EnableEndpointRouting = false;
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        
        app.UseRouting();
        app.UseMvc();
        
        Bot.GetBotClientAsync().Wait();
    }
}

@PiGi78 thank you very much !