I have this same issue on Xbox One.
My account works fine.
My son's account, when offline works fine. He can even load a game and start playing. But as soon as we Sign In to the minecraft store page the games crashes to the xbox dashboard.
When starting Minecraft while online the game will get to the profile sync screen then crash to dashboard.
If online and I start the game and choose to switch profiles to his, the game crashes to dashboard.
It may be related - his account is a child account on xbox live while I am an adult account.
Can confirm, this is resolved for xbox one. Child account is now able to play again! Thanks.