Unresponsive XS Max...black screen/apple logo only
iPhone XS Max constantly displays black screen with apple (though every several minutes the screen goes black momentarily and then apple logo reappears as if it's started to reboot). Phone will not turn off or on, or do a hard reboot. Doesn't respond to any combination of button pushes at all. Also, computer with iTunes installed doesn't recognize phone when it is plugged in. Any help out there?
Windows, Windows 10