This is very rare but Facebook, Instagram, and Whatsapp are down right now (04-10-2021). There is a major outage of some kind of resources because they share resources among them.
If you go to facebook right now, it will return 5XX error in the browser.
People who are using Facebook login are in big trouble right now, they can not log in to their apps using Facebook
There is possibly a DNS issue, facebook is working on it.