I have been receiving this message a lot today and looking around it seems that this error is rather generic. I receive this error whilst trying to access my Followers but it has also been associated with : Friends List Party Achievements Has anyone esle experienced this issue with the apps yet, or knows what it is exactly? After rebooting it was fine, but i was wondering if anyone else has had this error? I tried Xbox Support the error doesn't appear to exist lol!
get on live support and see what they say and if you get any answers that will help every one else out if they have the same issue
Here's a full tutorial on how to troubleshoot and resolve the error. http://www.xpgamesaves.com/topic/93235-how-to-fix-xbox-one-error-0x87c40000/
was having the same issue earlier thinking maybe I missed a service announcement thanks bullet for the tut