It's failing for me in 1.11.2 with the same issue. Also after failing the realms server cannot be accessed. Whenever I try to reset the world or open/close the server it takes forever not accomplishing anything. I also can't play on the server for a while after as well.
I've been trying it all day and still to no avail. It fails at 100% for me though, and when it is verifying the world.