If the problem is caused by serious system faults or flaws, a full system reset may be the answer. Everything, including your downloaded applications, personalized settings, multimedia files, and personal information, will be wiped during this reset. If you want to give it a chance, back up all of your important data to iCloud or iTunes first, then master reset your iPhone 8 Plus using the settings menu:

1. From the Home screen, choose Settings.
2. Select General.
3. Reset may be found by scrolling down and tapping it.
4. Erasing all content and settings is the option to choose.
5. Enter your device passcode if asked.
6. Then press to check that the system settings have been reset.