Factory Reset Your iPhone
If everything else fails, you can always erase all content on your iPhone. This basically means that you’ll factory reset your device and start from scratch.
Of course, this means you’ll lose all the data, apps, and files your iPhone has stored, so be sure to backup your iPhone before you even try to do this.
- Open the Settings app.
- Scroll down and go to General.
- Scroll down to the bottom and then select Transfer or Reset iPhone.
- Tap on Erase All Content and Settings.
- Tap on Continue and follow the instructions on your screen.