The old version of the page editor seems to break with large pages that have lots of images.
All I get is the useless bad UX It's taking longer than usual to load this page error, which is a lie because it's a bug with confluence.
It seems like activationid-services is returning a 429 too many requests error for some reason but only when editing large pages.
PS: Also your JavaScript is really poorly optimized their is way to many requests no wonder the page takes so long to load.
PPS: I would submit a bug report but thats broken as well.