Hi
It may help to follow these steps:
If you have not yet done so, update your iPhone to the latest version of iOS (currently iOS 10.1.1).
In respect of Wi-Fi connectivity:
- If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network - Apple Support
- Connect to Wi-Fi on your iPhone, iPad, or iPod touch - Apple Support
- Recommended settings for Wi-Fi routers and access points - Apple Support
In respect of cellular data connectivity: