Old certificate expired. Matt added new one. I have zero clue what that involves.
His effort only partially took so there was one day when some of us, yeah me too, couldn't get in. I called Matt and he fixed the issue. Everyone should now be able to get in. Let him know to check again, if still an issue for him Matt will need to be advised.
It's way over my technical skill level. I don't even know what a certificate is or why it's needed.