The authentic was a free component of the Windows Essentials suite provided by Microsoft. It never required a registration code or a licensed email to function.
These are not Microsoft products. They are clones designed to mimic the interface of the classic software. Unlike the original, these versions are often pay-to-use. They allow you to edit the video but place a massive watermark across the screen until you purchase a "registration code" and enter a "licensed email."
If you ignore the warning and search for a code on YouTube, torrent sites, or keygen websites, several things can happen: