Katalon cannot find hover scrollbar

I try to scroll down to expend dropdown list using
WebUI.waitForElementPresent(findTestObject(‘Loading_scrollbar’), 10)

WebUI.waitForElementClickable(findTestObject(‘Loading_scrollbar’), 30)


WebUI.scrollToElement(findTestObject(‘div_More’), 10)
and get error: “Unable to find the element located by 'By.xpath:…” The scrollbar which I try to scroll down can show up only when mouse hover on it.

Could any Katalon expert help? Thanks!