Thank you so much! Followed this fix and worked right away. It still wouldn't install normally for me before trying this, seems to be 3 days later still no fix from NowTV or Xbox... shambles. Cheers!!
I have had the same issue too, reading on the Xbox forums it seems the app was updated on 31st Jan and since then loads of accounts have been unaccesable on Xbox one. I have a now TV box which works fine but the Xbox app wouldnt load so I uninstalled and now can't install it again.
I have the same issue. Did a hard reset on my Xone deleted the app tried to reinstall and nothing. I now cannot view it at all it's been 3 days now. This is disgusting that nothing is being done..