How to Reset Network Settings on iOS devices
Resetting your network settings is usually something saved as a last resort. It can be a useful troubleshooting step for network issues on tablets, phones, and PCs. This process will completely wipe any custom network settings on your iOS device–including any previously-stored Wi-Fi networks or Bluetooth connections.
Note: *Resetting your network settings is not the same as Factory resetting your iOS device which wipes the memory entirely.