Disclaimer: Resetting your Network Settings will erase all your prior settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you’ve used before. 

A Network Settings reset will help fix any problems with Network settings not working correctly on your iOS device.

Step 1

Click on Settings

Step 2

Click on General. Scroll down and click on Reset

Step 3

Click on Reset Network Settings