Settings app closes seconds after I open it

This is a strange problem that started today. When I open the SETTINGS app (i.e., where you choose the WIFI network to connect to etc), it opens for a few seconds and then closes. I have rebooted my iPhone to see if that would fix it but it did not. This is the strangest iPhone problem I have encountered.

Has anyone else encountered this issue ?

Any suggestions on how to fix it ?