服务器响应错误：500 ASP.NET Core

我想用angular和asp做一个服装店，但是我遇到了将数据发送到数据库的困难。有一个用于注册和授权的模块化表格。首先，我决定实现注册表单，但是发送数据时出错：

我是新手，所以我附上了代码，因为我不知道错误的问题是什么。

用户.ts：

export class Users{
   id? = "";

   phone = "";

   email = "";

   fio = "";

   address ="";

   password = "";

}

用户服务.ts：

@Injectable({
  providedIn: 'root'
})
export class UserServiceService {

  private url = "User";

  constructor(private http: HttpClient) {
  }
  @Input() public createUser(users: Users): Observable<Users> {
    return this.http.post<Users>(
      `${environment.apiUrl}/${this.url}`,
      users
    );

导航菜单.ts：

export class NavMenuComponent {

  user:Users =new Users;
  @Output() userUpdated = new EventEmitter<Users>();
  constructor(private superHeroService: UserServiceService) {}
  createnewUser(users: Users) {
    this.superHeroService
      .createUser(users)
      .subscribe((users: Users) => this.userUpdated.emit(users));
  }

}

从输入中读取变量：

<div class="modal-body">
  <input [(ngModel)]="user.email" class="form-control">
  <input [(ngModel)]="user.phone" class="form-control">
  <input [(ngModel)]="user.address" class="form-control">
  <input [(ngModel)]="user.fio" class="form-control">
  <input type="password" [(ngModel)]="user.password" class="form-control"> :
  <input type="password" class="form-control">
</div>

后端：

用户控制器.cs：

[Route("api/[controller]")]
[ApiController]
public class UserController : Controller
{
    private readonly DataContext _context;

    public UserController(DataContext context)
    {
        _context = context;
    }
    [HttpPost]
        public async Task<IActionResult> CreateUser(User user)
        {
            _context.Users.Add(user);
            await _context.SaveChangesAsync();

            return Ok(await _context.Users.ToListAsync());
        }
}

数据上下文.cs：

public class DataContext : DbContext
{
    public DataContext(DbContextOptions<DataContext> options) : base(options)
    {
        Database.EnsureCreated();
    }

    public DbSet<User> Users => Set<User>();

}

User.cs：公共类用户

{
    public string? Id = string.Empty;

    public string Phone = string.Empty;

    public string Email = string.Empty;

    public string FIO = string.Empty;

    public string Password = string.Empty;

}