Facebook登录与codeigniter工作在本地主机，但不工作在服务器上

function fblogin(){
    $base_url=$this->config->item('base_url');
    $facebook = new Facebook(array(
        'appId' =>  $this->config->item('appID'), 
        'secret'=> $this->config->item('appSecret'),
    ));
    $user = $facebook->getUser();
    if($user){
        try{
            $user_profile = $facebook->api('/me');
            $params = array('next' => $base_url.'Poll/logout');
            $ses_user=array(
                'User' => $user_profile,
                'logout' => $facebook->getLogoutUrl($params)
            );
            $this->session->set_userdata($ses_user);
            header('Location: '.$base_url);
        }catch(FacebookApiException $e){
            error_log($e);
            $user = NULL;
        }       
    }
    echo error_log($e);
    $user = $this->session->userdata('User');
    echo $user['id'];
    $this->load->view('main');
}

当echo error_log($e)显示(1)var_dump(error_log($e))显示bool(true)

但在本地运行正常