I have a MacBook Pro with Sonoma. The fingerprint function has stopped working

I have always had the fingerprint function set up and use it. I has simply stopped being an option. On the login screen it no longer presented as an option. When using the password manager, the option to use either the fingerprint or password pop-up, just flashes and disappears.

I have shut down, restarted several times, I have switched off and on the setting in Touch Id and password (with restarts in between).

thoughts?

Guy