Open the Element and check whether the Selector still matches what is on the page. Layout and attribute changes are the usual cause when a Selector that used to work starts failing.
- Open the failed Test Step and note which Element it uses.
- Open that Element. Confirm it still matches the page object you can see.
- Prefer Selectors built for testing, such as a Test ID, when the application exposes one.
- Avoid Selectors that depend on generated class names, long auto IDs, or layout order that changes between releases.
- If that page object only appears after login, a menu, or a modal, add the steps that reveal it before the failing step.
- If it sits in a frame, add Switch frame before you interact with it.
- Re-run and compare the step responses for Existing and Displayed.
If the Element still cannot be found, open Help in DoesQA and select Create new ticket. Include the Run ID.
For choosing stable Selectors, see the docs: Choose durable selectors.