Outlook on iPad Pro frozen and preventing forced restart

Outlook app suddenly gave me a black screen on my new iPad pro. Can’t swipe up to get out of the program. If I allow the screen to shut down and then tap awake there is still the black screen. If I tap and tap the power button I can get to the lock screen. When I unlock I’m back to the black outlook screen. When I try to do a forced restart (trying both “hold down power plus one of the volume buttons for a long time” or “press and release volume up, press and release volume down, hold down power button” I get no response. So I have a black screen and forced restart doesn’t work. Ideas?