1.) Confirm that your iOS device, computer, and wireless plan all meet the system requirements for Personal Hotspot.
2.) Verify that Personal Hotspot is enabled by tapping Settings > General > Cellular > Personal Hotspot.
3.) Verify the Internet connection on your iOS device by tapping Safari and loading a new webpage.
4.) If one connection type doesn't work, try another (for example, instead of connecting using Wi-Fi, try using USB or Bluetooth).
5.) Try disabling and reenabling Personal Hotspot from Settings > Personal Hotspot or Settings > General > Cellular > Personal Hotspot.
6.) Install the latest version of iOS. Tap Settings > General > Software Update.
7.) Reset network settings by tapping Settings > General > Reset > Reset Network Settings.
8.) If none of the previous steps resolves your issue, restore the iPhone.
Depending on your cellular network connection, incoming or outgoing phone calls may interrupt your Personal Hotspot connection. After you end the call, Personal Hotspot should automatically reconnect with your devices.
If you are outside your wireless carrier's network coverage area, you may be roaming. If that is the case, you will need to have Settings > General > Cellular > Data Roaming set to On to use Personal Hotspot.
Data roaming charges will apply. Check with your wireless carrier if you are roaming to verify any additional charges.
When Personal Hotspot is enabled, your iOS device automatically shares your Internet connection with your computer when connected using USB.
Example: When you connect iPhone to your computer to charge or sync with iTunes. To avoid unnecessary data charges, turn off Personal Hotspot when not in use.