[gprasanth]

Suspecting it might be related to the recent letsencrypt cert authority expiring? Was just debugging an issue earlier today and just couldn't help wondering how much of the internet is secured by letsencrypt.

All of the static hosts providing free SSL: vercel, netlify, render, firebase hosting, github pages, heroku etc. ...

It does work on modern browsers and devices but goes terribly broken on a lot of old devices.

[jaywalk]

Obviously not possible to check right now to provide proof, but I feel quite confident in saying that Facebook does not use Let's Encrypt. It's also clearly not an SSL issue.

[gprasanth]

You're right. Fb doesn't seem to be using letsencrypt.

https://crt.sh/?q=facebook.com

On a side note, the amount of phishing sites using letsencrypt and having a domain similar to facebook.com is quite appalling.