selenium TimeoutException: in automating whatsap - python-3.x

Question

i am automating whatsap by using selenium and python script. I am trying to open chat by using xpath.it works well with recent chats, but when i try to open chat from contacts it raises TimeoutException.
here is my code:
import traceback
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.ui import WebDriverWait
import time
from selenium.common.exceptions import TimeoutException
from selenium.webdriver.support.wait import WebDriverWait
chrome_browser = webdriver.Chrome(executable_path = 'F:\driver\chromedriver.exe')
chrome_browser.get('https://web.whatsapp.com/')
time.sleep(15)
#print('scanning is completed')
wait = WebDriverWait(chrome_browser , 30)
user_name = "sakshi clg"
#user = chrome_browser.find_element_by_xpath('//span[#title="{}"]'.format(user_name))
#user.click()
#visibility_of_element_located element_to_be_clickable
#wait.until(EC.element_to_be_clickable(By.XPATH , "//span[#title=User_name]"))
try:
user=wait.until(EC.presence_of_element_located((By.XPATH ,"//span[#title='{}']".format(user_name))))
user.click()
except TimeoutException:
traceback.print_exc()
exception details:
Traceback (most recent call last):
File "C:/Users/DELL/PycharmProjects/whatsap_prj/main.py", line 25, in
user=wait.until(EC.presence_of_element_located((By.XPATH ,"//span[#title='{}']".format(user_name))))
File "C:\Users\DELL\PycharmProjects\whatsap_prj\venv\lib\site-packages\selenium\webdriver\support\wait.py", line 80, in until
raise TimeoutException(message, screen, stacktrace)
selenium.common.exceptions.TimeoutException: Message:
please someone help me.I am new to selenium.