Suddenly as of two hours ago I cannot edit with Cornerstone -- The option to do so is missing from top WP bar and when I attempt from Pages, this appears:
I have tried logging out and in. No luck. Also checked X -> Settings -> Permissions Permissions and all is checked properly. When I go to X -> Settings -> Cornerstone same page loads as screenshot above. (Same thing for Theme Options, Templates, Global Blocks).
X automatically updates 6.2.5, no other changes to site today.