1.Try again restart your phone. If your phone continues to be unable to start,go to the next step2.Erase app dataDeleting app configuration data may allow your phone to start in Safe mode. Safe mode allows access to basic functions ,so you can back up any important data stored on your phone,After backing up your data, a factory reset may be needed to get your phone to start normally .3.Visit a service center If you don't want to erase your app data or your phone still doesn't start, visit a service center for assistance.