Jul 5th 2023, 10:00:41
It's just because the security certificate isn't valid. As long as you don't enter your CC number or any passwords on sites like that, they're generally not going to cause you problems. Just go to advanced -> continue to site (unsafe).
That all said, the guides that are on there are massively outdated to the changesets and are largely unusable in the current meta. It's better to just ask the community questions.