在Android中创建QBPrivateChatManager获取错误nullpointer

创建Quickblox聊天，但创建时间获得nullpointer。

QBPrivateChatManager privateChatManager = QBChatService.getInstance().getPrivateChatManager();
            privateChatManager.createDialog(sub_arr.get(position).getOccupentId(), new QBEntityCallbackImpl<QBDialog>() {
                @Override
                public void onSuccess(QBDialog dialog, Bundle args) {
                     Log.d("dialog1", dialog+"");
                }

                @Override
                public void onError(List<String> errors) {

                }
            });