How to reset the network settings
Note: Wi-Fi network and passwords, mobile data settings, VPN and APN settings that you have used will be reset when you reset network settings.
1. Touch Settings.
2. Touch General.
3. Scroll to and touch Transfer or Reset iPhone.
4. Touch Reset.
5. Touch Reset Network Settings.
If required, enter your passcode.
6. Touch Reset Network Settings.
7. Your iPhone will now restart.