Good Plugin and Excellent technical support

When I install this plugin on the website, it’s not working. The protected files still can be opened directly with URL. The website is on a Windows Server, using IIS. I guess it maybe the issue but I can’t finger out how to fix it. Tried contact them for help without hope, because it’s a free plugin. But I got response in an hour, and a tech guy took 1 day to fix all issues. Thank you a million, you are the best.