This morning, I can log correctly in; and even access the "Password and Authentication" tab.

Enabling dual-factor authentication doesn't work though. The UI is visible but inactive.

@Alfredbali you might want to try again today.

AF.com IT is really a disgrace. Over the past 24h, I tried to enable 2FA a few times. I saw the format of requests change, as well as the endpoints. They are tinkering to make it work (and it still doesn't). Doing this kind of work on a live server would be unacceptable for any small business which depends on the web to interact with customers. How such a large company can keep working like this for years is beyond understanding.