Screen Shot Comparison Tool doesn`t work

Hey,
i`m trying to figure out how the screenshot comparison tool works. I´m following the instructions listed in this article from the unreal docs. I´m repeating the steps from the article, but the tool doesn’t seem to take any screenshots, also the Automation Test is finished in less than a second. Are there any prerequisites that are missing in the article ? Is anyone experiencing the same problems ? In the answer hub i couldn’t find anything helpful .

Same problem, no any answer!