This is a known issue. According to Apple you should:
"Try the following steps and attempt to enable Wi-Fi or Bluetooth after each one." 1. Verify that Airplane Mode is off. 2. Restart your iOS device. 3. Update your iOS device. 4. Reset Network Settings, by tapping Settings > General > Reset > Reset Network Settings. 5. Restore your iOS device in iTunes.
Hope this helps.
Comments
This is a known issue. According to Apple you should:
"Try the following steps and attempt to enable Wi-Fi or Bluetooth after each one."
1. Verify that Airplane Mode is off.
2. Restart your iOS device.
3. Update your iOS device.
4. Reset Network Settings, by tapping Settings > General > Reset > Reset Network Settings.
5. Restore your iOS device in iTunes.
Hope this helps.