It says that element cannot be found in selenium.

selenium.common.exceptions.NoSuchElementException: Message: Unable to find element with xpath == //li/a[@id='a_0111060000']

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.common.exceptions import NoSuchElementException

import os
import time
driver = webdriver.Ie()
driver.get("http://www.hometax.go.kr")

driver.find_element_by_xpath("//li[@id='group1299']").click()
time.sleep(2)

driver.switch_to_frame(driver.find_element_by_tag_name('iframe'))
time.sleep(2)
driver.find_element_by_xpath("//li/a[@id='a_0111060000']").click()