Thread:Brandon Rhea/@comment-38428405-20190207164525/@comment-34888194-20190207205745

That's because mobile editing is disabled since August 2018 according to thisthread.

And you can still edit in mobile, but you have to edit in desktop version. Scroll all the way down, and tap "View Full Site". Then, you are on desktop mode and you can edit as if you are edit on a PC.