My certificate has expired

Figured it out, my son had change time setting to set time manually instead of automatically so he could cheat a game. Set it back to set time automatically everything's fine.

I am having this issue too, not only on Facebook but all apps cannot connect to authentication servers. I am on strong wifi, verified by ookla speed test app, but all apps are failing when trying to access account info while facebook app give the above message. Something happened to SSL. I'm on iOS 14.2.

This seems like a FaceBook issue.

Facebook is not an Apple product. Contact the app developer here --> App Support