Catalogo recebendo null

Ainda estou tendo o erro de nullException using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Microsoft.AspNetCore.Builder; using Microsoft.AspNetCore.Hosting; using Microsoft.AspNetCore.Http; using Microsoft.Extensions.DependencyInjection;

namespace web { public class Startup { // This method gets called by the runtime. Use this method to add services to the container. // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940 public void ConfigureServices(IServiceCollection services) { services.AddTransient<ICatalogo,Catalogo>(); }

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env, IServiceProvider serviceProvider)
    {
        if (env.IsDevelopment())//Gera a pagina dentro desse metodo
        {
            app.UseDeveloperExceptionPage();
        }
        ICatalogo  catalogo  = serviceProvider.GetService<Catalogo>();
        IRelatorio relatorio = new Relatorio(catalogo);
        app.Run(async (context) =>
        {
            await relatorio.Imprimir(context);

        });
    }
}

}