Sometimes 2FA does not works

The SCLogin module uses Javascript to query Joomla if the user that's trying to login has 2FA enabled. If that check comes back as false, then you won't see the 2FA field. I don't know of a reason why that check would come back as false if the user has it enabled, but hopefully that information helps narrow things down. Specifically, if it's happening for a specific user, look to see if there's something different about their 2FA configuration or something else that may stand out. Any details you can provide will definitely help.

Thanks,
Alex

I don't know what browser you're using, but can you try to open the Developer Tools.In the "Network" tab, hit "Preserve Log". Then try to login.

If it fails, check the Network tab and see if any requests are marked with 400 (or higher) error codes. If so, let us know what those URLs are.
Then, in the Javascript Console console, check if there are messages or other error messages that may be related to our Javascript check to see if the user has 2FA enabled.

One other thing to check is in the Global Configuration area of Joomla. Set the Error Reporting setting to 'None'. While I don't know of any PHP warnings or errors our check causes, if some other extension is causing a PHP message to be thrown, that could prevent our code from executing properly.

I hope that helps, but if not, please let us know.

Thanks,
Alex