Why is Touch ID not working when connecting to iTunes?

In past couple of days when trying to connect iphone to computer (to update) via iTunes as in the past I am being asked to "Trust Computer" which I do, then to "Touch On" which I attempt to. It doesn't work. I have enabled "itunes and app store" in Touch Id & passcode on iphone. I have turned both devices off/on, bot devices are up to date, I have updated fingerprint etc etc. Nothing seems to make it work.

[Re-Titled by Moderator]