Can't display Codeigniter validation error

Can't display Codeigniter validation error::

#login.php - CONTROLLER

function index () {
    $data ['content'] = "login_form";
    $this->load->library("form_validation");
    $this->form_validation->set_rules('email' , 'email' , 'trim|xss_clean|required');
    $this->form_validation->set_rules('password' , 'password' , 'md5|trim|required');
    if( $this->form_validation->run() == FALSE) {
          $this->load->view("template", $data);
    }
    else {
        redirect("user/profile");
     } 
}

#login_form.php - VIEW

<?php echo validation_errors(); ?>
<?php echo form_input('email' , 'email'); ?> <br>
<?php echo form_input('password' , 'password'); ?> <br>
<?php echo form_submit('submit' , 'submit'); ?>