I am very sorry, but I wouldn't rely on such checkers to know the websites' status. They can be misleading very often. That checker didn't even update some domains to reflect the new ones. For example, X is still shown there as twitter.com, and incorrectly detected as being down, even though I can access it fine. Other websites like WhatsApp (whatsapp.com) and Reddit (reddit.com) are also incorrectly detected as being down, even though I can access both websites fine.
Checking the websites' status (when they post status updates) on their social media in fact is enough, and also has up to date information, instead of relying on a checker online.
And here's a screenshot of being able to access archive.org normally without any issues, taken today.