What if the iPhone can't connect to the App Store?

Restart iPhone

Press the Sleep/Wake button and the Home button at the same time until the Apple logo appears on the screen, and then restart the iPhone.

Reset all settings

Some users select "Settings" in turn; "General"-"Reset"-"; Reset all settings solved this problem. Users need to re-enter the password, change the wallpaper and reset the touch ID, but the user's data will not be deleted.

Backup data

Some users reported that the problem was solved by restoring the factory settings, but all the information on the mobile phone would be lost, so users need to back up the data first. Users may need to set up their iPhone like a new phone, and some users said that restoring the backed-up data from iTunes or iCloud would make this problem reappear.