1. 确保在应用程序程序池中使用的用户具有数据库读/写权限。

2. 确保在AppSettings中配置正确的Identity连接字符串，包括正确的用户名和密码。

3. 在项目中确保添加了Identity和Authentication middleware。以下是在Startup.cs中添加身份验证中间件的示例：

using Microsoft.AspNetCore.Authentication.Cookies;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using System;

public class Startup
{
    IConfiguration Configuration { get; }

    public Startup(IConfiguration configuration)
    {
        Configuration = configuration;
    }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllersWithViews();

        services.AddDbContext(options =>
            options.UseSqlServer(
                Configuration.GetConnectionString("DefaultConnection")));

        services.AddIdentity(options =>
        {
            options.Password.RequireNonAlphanumeric = false;
            options.Password.RequireDigit = false;
            options.Password.RequireLowercase = false;
            options.Password.RequireUppercase = false;
            options.Password.RequiredLength = 6;
            options.SignIn.RequireConfirmedEmail = false;
            options.SignIn.RequireConfirmedPhoneNumber = false;
        })
            .AddEntityFrameworkStores()
            .AddDefaultTokenProviders();

        services.ConfigureApplicationCookie(options =>
        {
            options.Cookie.HttpOnly = true;
            options.ExpireTimeSpan = TimeSpan.FromMinutes(20);

            options.LoginPath = "/Login";
            options.AccessDeniedPath = "/Account/AccessDenied";
            options.LogoutPath = "/Logout";

            options.SlidingExpiration = true;
        });

        services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme)
            .AddCookie(options =>
            {
                options.ExpireTimeSpan = TimeSpan.FromMinutes(20);
                options.LoginPath = "/Login";
                options.LogoutPath = "/Logout";
                options.Cookie.HttpOnly = true;
            });

        services.AddAuthorization(options =>
        {
            options.AddPolicy("AdminOnly", policy =>
                policy.RequireRole("Administrators")
                    .Build());
        });
    }

    public void Configure(IApplicationBuilder app, IWebHostEnvironment env