Y0utube.best is a dubious website where its pop-ups are social engineering attacks luring users into clicking “allow” should they wish to proceed accessing the page. Once you allowed subscribing into its push notifications, you will start seeing unwanted ads, banners, fake error messages and software updates, clickbait links for online games, adult sites and the likes.
Clicking any of these advertisements will send you to malicious websites to get money from you or infect your computer further. It may also prevent you from changing your settings back and monitor your browsing activities. Remove Y0utube.best immediately before it will damage your computer further.