Yii user authentication and session not working

I am building a website in Yii and I am stuck at the user authentication step. Whatever i do I am not able to authenticate users or store some value in the session. My UserIdentity component is as follows: ``` class UserIdentity extends CUserIdentity { private $_id; public function authenticate(){ if(($userRecord = Admin::model()->findByAttributes(array('username'=>$this->username)))===null){ return $this->errorCode=self::ERROR_USERNAME_INVALID; } if($userRecord->password!=hash('sha256', $this->password)){ return $this->errorCode=self::ERROR_PASSWORD_INVALID; } $this->_id=$userRecord->id; $this->setState('title', $userRecord->username); Yii::app()->session['clientId'] = $userRecord->clientId; Yii::app()->session['id'] = $userRecord->id; Yii::app()->session['loggedin'] = true; return $this->errorCode=self::ERROR_NONE; } public function getId(){ return $this->_id; } } ``` My `Yii:app()->user->isGuest` always returns true and `Yii::app()->user->id` returns nothing. That is why I tried using `Yii::app()->session['loggedin']` to do authentication. But even that is not working. When I access session array like this `Yii::app()->session` I get the error `Property "CWebUser.session" is not defined.`. This is getting really frustrating. I am new to Yii. Please help.