DI issues with custom user manager class

Question

I have issue with DI. I get System.InvalidOperationException: Unable to resolve service for type 'Microsoft.AspNetCore.Identity.UserManager`1[PupilRegister.Models.Entities.Parent]. Case: I need to get logged in user ID. This is why I need to use UserManager. Full source code: https://github.com/Nemes1sX/PupilRegister

AuthController.cs

ing Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.IdentityModel.Tokens;
using PupilRegister.Configuration;
using PupilRegister.Interfaces;
using PupilRegister.Models.FormRequest;
using System;
using System.IdentityModel.Tokens.Jwt;
using System.Security.Claims;
using System.Text;
using Microsoft.Extensions.Options;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Identity;
using PupilRegister.Models.Entities;

namespace PupilRegister.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class AuthController : ControllerBase
    {

        private readonly IUserService _userService;
        private readonly UserManager<Parent> _userManager;
        private readonly JwtConfig _jwtConfig;

        public AuthController(IUserService userService, IOptions<JwtConfig> jwtConfig, UserManager<Parent> userManager)
        {
            _userService = userService;
            _userManager = userManager;
            _jwtConfig = jwtConfig.Value;
        }


        [HttpPost]
        [Route("login")]
        public IActionResult Authenticate([FromBody] LoginRequest request)
        {
            var parent = _userService.Authenticate(request.Email, request.Password);

            if (parent == null)
                return BadRequest(new { message = "Username or password is incorrect" });

            var tokenHandler = new JwtSecurityTokenHandler();
            var key = Encoding.UTF8.GetBytes(_jwtConfig.Secret);
            var tokenDescriptor = new SecurityTokenDescriptor
            {
                Subject = new ClaimsIdentity(new Claim[]
                {
                    new Claim(ClaimTypes.Name, parent.Id.ToString())
                }),
                Expires = DateTime.UtcNow.AddDays(7),
                SigningCredentials = new SigningCredentials(new SymmetricSecurityKey(key), SecurityAlgorithms.HmacSha256Signature)
            };
            var token = tokenHandler.CreateToken(tokenDescriptor);
            var tokenString = tokenHandler.WriteToken(token);

            // return basic user info and authentication token
            return Ok(new
            {
                Token = tokenString,         
            });
        }

        [Authorize]
        [HttpGet]
        [Route("get")]
        public async Task<IActionResult> GetUserId()
        {
            var user = await _userManager.GetUserAsync(HttpContext.User);

            return Ok(user.Id);
        }

Parent.cs

using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;

namespace PupilRegister.Models.Entities
{
    [Table("Parent")]
    public class Parent
    {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        [Key]
        public int Id { get; set; }
        [Required]
        public string Name { get; set; }
        [Required]
        public string Email { get; set; }
        public byte[] PasswordHash { get; set; }
        public byte[] PasswordSalt { get; set; }
        public virtual List<Pupil> Pupils { get; set; }
    }
}

Startup.cs

using Microsoft.AspNetCore.Authentication.JwtBearer;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.IdentityModel.Tokens;
using PupilRegister.Configuration;
using PupilRegister.DataContext;
using PupilRegister.Infrastructures;
using PupilRegister.Interfaces;
using PupilRegister.Services;

using System.Text;
using System.Threading.Tasks;
using Newtonsoft.Json;


namespace PupilRegister
{
    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.AddScoped<IUserService, UserService>();
            services.AddCors();
            services.AddControllers();
            services.AddControllers().AddNewtonsoftJson(x =>
               x.SerializerSettings.ReferenceLoopHandling = ReferenceLoopHandling.Ignore);
            services.AddScoped<IUserService, UserService>();
            //services.AddIdentityCore<Parent>();
            services.AddScoped<IPupilService, PupilService>();
            services.AddScoped<Mapping>();
            var appSettingsSection = Configuration.GetSection("AppSettings");
            services.AddDbContextPool<PupilRegisterContext>(options =>
                options.UseSqlServer(Configuration.GetConnectionString("PupilRegisterDatabase")));
            services.Configure<JwtConfig>(appSettingsSection);

            // configure jwt authentication
            var appSettings = appSettingsSection.Get<JwtConfig>();
            var key = Encoding.ASCII.GetBytes(appSettings.Secret);
            services.AddAuthentication(x =>
            {
                x.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                x.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
            })
            .AddJwtBearer(x =>
            {
                x.Events = new JwtBearerEvents
                {
                    OnTokenValidated = context =>
                    {
                        var userService = context.HttpContext.RequestServices.GetRequiredService<IUserService>();
                        var userId = int.Parse(context.Principal.Identity.Name);
                        var user = userService.GetById(userId);
                        if (user == null)
                        {
                            // return unauthorized if user no longer exists
                            context.Fail("Unauthorized");
                        }
                        return Task.CompletedTask;
                    }
                };
                x.RequireHttpsMetadata = false;
                x.SaveToken = true;
                x.TokenValidationParameters = new TokenValidationParameters
                {
                    ValidateIssuerSigningKey = true,
                    IssuerSigningKey = new SymmetricSecurityKey(key),
                    ValidateIssuer = false,
                    ValidateAudience = false
                };
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthentication();
            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }
}