Accessing a custom object with instanceof

The specific error is: Class 'LN_Account' not found

The model is like this:

PHP Code:

namespace App\Models;
use CodeIgniter\Model;
use App\Libraries\LN_Account;

Class AuthenticationModel extends Model {
    public function getAuthenticationCredentials($account) {
        if ($account instanceof LN_Account) {
            $sql = "SELECT * FROM ln_authentication WHERE username = ?";
            $query = $this->db->query($sql, array($credentials->username));
            $account = $query->getCustomRowObject(0, 'LN_Account');
        }
        return $account;
    }
} 


---

LN_Account is in app\Libraries

PHP Code:

namespace App\Libraries;

class LN_Account {
    ....
} 


---

if I print_r $credentials inside the model/method I get this, so the controller knows what it is and created it. 

PHP Code:

App\Libraries\LN_Account Object
(
    [id] => 0
    [username] => admin@domain.com
    [password] => 
    [password_key] => 0
    [password_key_timeout] => 0
    [status] => 
    [created_at] => 0
    [updated_at] => 0
    [deleted_at] => 0
) 


---

Okay so the outer if ($account instanceof LN_Account) seems to work now, it's this that doesn't:

$credentials = $query->getCustomRowObject(0, 'LN_Account')

Do I have to instantiate a new LN_Account() for it to use? I figured it would do it automatically.