ASP.NET Signinmanager error

Question

I have error in Visualstudio in Signinmanager.

private readonly SignInManager<Utilizador> _GerirLogin;

I have another private readonly to be used and have no mistake:

private readonly UserManager<Utilizador> _GerirUtilizadores;

I have them all using and the error message is as follows:

Type or namespace name "Signinmanager<>" cannot be found.

Using in use :

using Gestaocondominios.BLL.Models; using Gestaocondominios.DAL.Interfaces; using Microsoft.AspNetCore.Identity; using System; using System.Collections.Generic; using System.Text; using System.Threading.Tasks;