pizzaboy9oo

Try to :
1. use other sim card
2. turn on air plane mode and turn off again
3. reset network settings in general > reset > reset network settings
4. software update in general > software update > update
5. go to settings > phone > sim pin > turn sim pin 'off'
6. login iCloud in settings > account login

Now you may solve the problem by trying those methods, hope it helps.