Selenium: MoveTargetOutOfBoundsException: move target out of bounds

An Actions API command (ActionChains in Python, Actions in Java) tried to move the mouse pointer to a point outside the browser's viewport. WebDriver's pointer actions work in viewport coordinates and do not scroll automatically for offsets, so if the target point is off-screen, the move is rejected.

It most often follows move_to_element or move_to_element_with_offset on an element below the fold, or offsets calculated for a larger screen. Since Selenium 4, offsets for move_to_element_with_offset are measured from the element's center, not its top-left corner, so code written for Selenium 3 can now aim outside the element and the viewport. Small headless window sizes (800x600 by default in some setups) make it more likely.

What is not wrong: the element exists and was found; the pointer target is simply unreachable from the current scroll position.

from selenium.webdriver.common.action_chains import ActionChains
from selenium.webdriver.common.by import By

slider = driver.find_element(By.CSS_SELECTOR, "#price-slider .handle")
ActionChains(driver)\
    .scroll_to_element(slider)\
    .click_and_hold(slider)\
    .move_by_offset(60, 0)\
    .release()\
    .perform()

Use a fixed, realistic window size in every environment, scroll elements into view before pointer actions, and compute offsets from element dimensions rather than hard-coded pixels. Prefer element-level methods over raw coordinates wherever possible, and revisit offset math when upgrading from Selenium 3.