Unable to verify object is visible - object is null

I have used “verifyElementVisible” command to verify alert present or not.
But when executing console showing following error.


An alert is not an element. If the thing you’re trying to verify is a genuine alert (ie a window.alert dialog) then you need to use one of the WebUI alert methods: https://docs.katalon.com/display/KD/[WebUI]+Alert

If you are using the term alert incorrectly for an actual element on the page, then you need to fix the call that is missing a reference to an object – the one that says ‘Object_Repository/’. It should have something added at the end, the name of the element stored in the Object Repository. Right now it’s saying null because there’s nothing there.