A hard reboot simply resets the phone by forcing it to shut down and then restart normally. This process is very helpful for minor firmware and app errors, therefore you should try it for this problem as well. Here's how to do it:
- Hold down the On/Off button for a few seconds.
- Press and hold the Home key while holding down the On/Off button.
- Keep both keys pressed until the screen goes off and on again.
Experiment with turning off LTE.
While LTE is improving, it has yet to reach a state of stability. As a result, it's unavoidable that it clashes with other frequencies at times. Users have reported that disconnecting LTE solved their difficulties, thus the instructions following could be worthwhile...
- On your iPhone, open the Settings app.
- Select Cellular.
- Select LTE from the drop-down menu.
- Select either Data Only or No Data. or Off.
- Reboot your iPhone 7.
