Неоднозначность между «Startup.Configuration» и «Startup.Configuration»

Question

Я получаю сообщение об ошибке «Неоднозначность между« Startup.Configuration »и« Startup.Configuration »» в моем классе запуска. Я не знаю, что я сделал, чтобы вызвать эту проблему. Я только создал класс DBContext, и эта ошибка произошла. Пожалуйста, смотрите мой код ниже:

Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.SpaServices.AngularCli;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.EntityFrameworkCore;
using Microsoft.AspNetCore.Identity;
using System;
using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.IdentityModel.Tokens;
using System.Text;
using IssueTracker.Data;

namespace IssueTracker
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

            // In production, the Angular files will be served from this directory
            services.AddSpaStaticFiles(configuration =>
            {
                configuration.RootPath = "ClientApp/dist";
            });

            // Enabling CORS
            services.AddCors(options => 
            {
                options.AddPolicy("EnableCORS", builder => 
                {
                    builder.AllowAnyOrigin().AllowAnyHeader().AllowAnyMethod().AllowCredentials().Build();
                });
            });

            // Connect to the Database
            services.AddDbContext<ApplicationDbContext>(options => options.UseSqlServer(Configuration.getConnectionString("DefaultConnection")));
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseCors("EnableCORS");

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseSpaStaticFiles();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller}/{action=Index}/{id?}");
            });

            app.UseSpa(spa =>
            {
                // To learn more about options for serving an Angular SPA from ASP.NET Core,
                // see https://go.microsoft.com/fwlink/?linkid=864501

                spa.Options.SourcePath = "ClientApp";

                if (env.IsDevelopment())
                {
                    spa.UseAngularCliServer(npmScript: "start");
                }
            });
        }
    }
}

ApplicationDbContext

using IssueTracker.Models;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;

namespace IssueTracker.Data
{
    public class ApplicationDbContext : IdentityDbContext<IdentityUser>
    {
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : base(options) {}

        // Creating the roles
        protected override void OnModelCreating(ModelBuilder builder) 
        {
            base.OnModelCreating(builder);

            builder.Entity<IdentityRole>().HasData(
                new { Id = "1", name="Admin", NoralizeName = "ADMIN" },
                new { Id = "1", name="Customer", NoralizeName = "CUSTOMER" },
                new { Id = "1", name="Moderator", NoralizeName = "MODERATOR" }
            );
        }

        public DbSet<ProductModel> Products { get; set; }
    }
}

Не могли бы вы сказать мне, что здесь не так? Спасибо.