If you can't connect to the internet, send or receive email and/or messages (text, picture or video), resetting the network settings may help.
Performing these steps resets all system settings (e.g., ringtones, sound settings, display settings, etc.) back to their default values. Personal data such as downloaded apps and media (pictures, videos, music) aren't affected.
From a Home screen, swipe up then navigate: Settings > General management.