Selenium: TimeoutException (WebDriverWait timed out)

Most of the time this comes from an explicit wait. WebDriverWait evaluated your expected condition every 500 ms until the timeout and it never returned a truthy value. In Python the message is often empty (Message: followed by nothing), because the binding raises it without text unless you pass a message to until(). The Java binding describes the condition and the polling interval.

It can also come from the browser: if a page load exceeds the page load timeout (300 seconds by default), driver.get() raises it, and ChromeDriver may report timeout: Timed out receiving message from renderer. Script timeouts from async JavaScript have their own ScriptTimeoutException.

What is not wrong: the wait mechanism. The condition you waited for genuinely did not happen in time, so ask why it did not.

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

options = webdriver.ChromeOptions()
options.page_load_strategy = "eager"
driver = webdriver.Chrome(options=options)
driver.get("https://example.com/login")
try:
    WebDriverWait(driver, 10).until(
        EC.visibility_of_element_located((By.ID, "login")),
        "login field never became visible",
    )
except TimeoutException:
    driver.save_screenshot("timeout.png")
    raise

Always give waits a descriptive message and capture a screenshot on failure, so timeouts explain themselves. Wait for the weakest condition that is sufficient for the next step. Do not mix implicit and explicit waits; Selenium's documentation warns the combination can produce unpredictable wait times.