How to fix an iPhone 8 Plus that is stuck on black screen with notification lights

Plug your iPhone into a wall socket and let it charge for a few minutes to ensure it doesn't run out of juice and won't come on. If your iPhone charges or displays a charging indication when hooked into the charger, consider forcing a restart while it's charging. This will assist in resolving any mistake that may have caused your phone to unexpectedly lose power. Simply follow the procedures outlined above to force your iPhone 8 Plus to restart, but this time do it while the phone is plugged into the charger. If at all feasible, charge your smartphone with the original charger.