Laravel 5.2 Custom Auth fail after next request - php

Question

I write a custom user provider to validate my user in a external API on external server.
CustomUserProvider:
<?php
namespace App\Auth;
use Illuminate\Auth\GenericUser;
use Illuminate\Contracts\Auth\Authenticatable as Authenticatable;
use Illuminate\Contracts\Auth\UserProvider;
use Psr\Http\Message\ResponseInterface;
use Illuminate\Http\Request;
use App\XXX\Facades\XXXX;
use Log;
class CustomUserProvider implements UserProvider {
public $errors = [];
public function getErrorMessages ( ) {
return $this->errors;
}
public function retrieveById($identifier)
{
// TODO: Implement retrieveById() method.
}
public function retrieveByToken($identifier, $token)
{
// TODO: Implement retrieveByToken() method.
return null;
}
public function updateRememberToken(Authenticatable $user, $token)
{
// TODO: Implement updateRememberToken() method.
}
public function retrieveByCredentials(array $credentials)
{
$response =APIService::get( 'GET', $credentials, 'tokens');
if ( array_key_exists('code', $response) ) {
/* Exception o Credentials Error */
$this->errors = $response;
return null;
} else {
$apiCredentials = json_decode( $response->getBody(), true );
if( $apiCredentials ) {
$attributes = array (
'id' => 1,
'name' => 'Name',
'lastname' => 'LastName',
'email' => 'email#email.com'
);
$user = new GenericUser( $attributes );
return $user;
}
}
return null;
}
public function validateCredentials(Authenticatable $user, array $credentials)
{
if( $user->email == $credentials['email'] ) {
return true;
}
return false;
}
}
The problem is that the user if logged fine, but in the next request Auth::user() returns false. Debugging in the middleware Auth:user() is returning false too.