I keep getting "The response ended prematurely" when invoking Web api in .net core tests

Question

I'm using Specflow as BDD testing framework and Fluent docker to spin up API container before each tests using docker compose file.

I put a breakpoint before sending a http request to test if the container is up and my app is running perfectly.

I open app swagger and hit endpoints and everything works. I added http request logging to check if request url is valid. Everything seems to be configured properly until this line:

var response = await _httpClient.PostAsJsonAsync(UserEndpoint, request);

This is console log

and this is my app Program.cs

using Ardalis.ListStartupServices;
using Autofac;
using Autofac.Extensions.DependencyInjection;
using UserSegmentation.Core;
using UserSegmentation.Infrastructure;
using UserSegmentation.Infrastructure.Data;
using UserSegmentation.Web;
using Serilog;
using UserSegmentation.Application;

var builder = WebApplication.CreateBuilder(args);

builder.Host.UseServiceProviderFactory(new AutofacServiceProviderFactory());

builder.Host.UseSerilog((_, config) => config.ReadFrom.Configuration(builder.Configuration));

// builder.Services.Configure<CookiePolicyOptions>(options =>
// {
//   options.CheckConsentNeeded = _ => true;
//   options.MinimumSameSitePolicy = SameSiteMode.None;
// });

var connectionString =
  builder.Configuration
    .GetConnectionString("SqliteConnection"); //Configuration.GetConnectionString("DefaultConnection");

builder.Services.AddDbContext(connectionString!);

builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
// add list services for diagnostic purposes - see https://github.com/ardalis/AspNetCoreStartupServices
builder.Services.Configure<ServiceConfig>(config =>
{
  config.Services = new List<ServiceDescriptor>(builder.Services);

  // optional - default path to view services is /listallservices - recommended to choose your own path
  config.Path = "/listservices";
});


builder.Host.ConfigureContainer<ContainerBuilder>(containerBuilder =>
{
  containerBuilder.RegisterModule(new DefaultCoreModule());
  containerBuilder.RegisterModule(
    new DefaultInfrastructureModule(builder.Environment.EnvironmentName == "Development"));
  containerBuilder.RegisterModule(
    new ApplicationModule());
});

builder.Services.AddHealthChecks();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
  app.UseSwagger();
  app.UseSwaggerUI();
  app.UseShowAllServicesMiddleware();
}

// app.UseHttpsRedirection();

app.UseAuthorization();

app.MapControllers();

app.UseFluentValidationExceptionHandler();

app.MapHealthChecks("/healthz");

// Seed Database
using (var scope = app.Services.CreateScope())
{
  var services = scope.ServiceProvider;

  try
  {
    var context = services.GetRequiredService<AppDbContext>();
    context.Database.EnsureCreated();
    SeedData.Initialize(services);
  }
  catch (Exception ex)
  {
    var logger = services.GetRequiredService<ILogger<Program>>();
    logger.LogError(ex, "An error occurred seeding the DB. {exceptionMessage}", ex.Message);
  }
}

app.Run(); 

My hooks config

[BeforeScenario]
  public void SetupClient()
  {
    var config = LoadConfiguration();
    var apiUrl = config["Users.Api:BaseAddress"] ?? "http://localhost:8080";
    var httpClient = new HttpClient(new LoggingHandler(new HttpClientHandler())) {
      BaseAddress = new Uri(apiUrl)
    };
    
    httpClient.DefaultRequestHeaders.Add("accept", "*/*");
    _objectContainer.RegisterInstanceAs(httpClient);

    var dockerConfig = new DockerConfiguration();
    _objectContainer.RegisterInstanceAs(dockerConfig);
  }

  
  [BeforeTestRun]
  public static void DockerComposeUp(DockerConfiguration dockerHandling)
  {
    dockerHandling.DockerComposeUp();
  }
  
  [AfterTestRun]
  public static void DockerComposeDown(DockerConfiguration dockerHandling)
  {
    dockerHandling.DockerComposeDown();
  }

My docker config

_compositeService = new Builder()
      .UseContainer()
      .UseCompose()
      .FromFile(dockerConfigurationFile)
      .WaitForHttp("user-segmentation", "http://localhost:8080/healthz", 
        continuation: (resp, _) => resp.Code == HttpStatusCode.OK ? 0 : 2000)
      .RemoveOrphans()
      .Build()
      .Start();