calendar, phone and reminder apps on iPhone are empty

[iMore Question]

My iPhone just worked fine, for more than a year.
Suddenly, now I have many issues, just since a few days (don't know why, have not upgraded iOS lately):

- the 'phone' app doesn't display 'contact'-button anymore (only 'recent', 'keys' and 'voicemail'),
and all recent calls are 'unknown' while they're all calls from people in my contacts. (However, when I open my 'contacts' app directly, i can see all my contacts.
- agenda / calendar app is empty: 'this app has no authorisation to your agendas/calendars' -> 'You can turn it on in 'Privacy' in 'Settings' -> which also isn't possible anymore
- same story for 'reminders' app: it's empty
- 'notes' app is not empty, still works fine, 'contacts' app is also complete, I can still make my phone calls from here.

So, no data is lost, but these apps are not connecting anymore. In 'Settings' -> 'Pivacy', all apps are 'empty': no apps are asking for permission to use any app.

I can't find any related topic on this anywhere online. Someone can help here?

 

[Just_Me_D]

If it were me, I would start from scratch. I would put my iPhone in DFU mode then restore it via iTunes. After that, I would set it up as a new device.