I can't load any apps on the new iPhone SE

I can't load the TestFlight app on my new iphone SE.

In fact a can't load any app from the app store.

• Restarted phone (it was off during the night)
• loged out of the app store & logged back in
• checked wlan connection (all fine). tested on another wlan
• checked 4g connection (all fine)

¯\_(ツ)_/¯