Face ID Not Working [Fixed. Please see the approved answer for details.]

I’m reading similar comments in a lot of these posts, that people have reset their phone settings, which I’ve never done and would only do if there were some serious issue with the device. So I’m wondering if Face ID is an issue with those who have not reset their settings. I have also seen in other threads that changing the duration to 1 week instead of 2 has seemed to resolve the issue, at least for a time. I’m wondering if that holds true.

We’re still using 1P7 at this point since there are no issues that I’m aware of and it offers everything that 8 does for our purposes. But I do like to use the latest versions of of critical apps that are regularly used so I may migrate us to 8 at some point. So I’m holding off for now but if the Face ID issue is caused by users resetting their phone settings then I don’t see that as an issue that would give me any concern. If it’s caused by selecting a duration - 2 weeks - then that is an issue that needs to be addressed before I would migrate to 8.