Comment by jmmv
I encountered this a while ago and it was incredibly frustrating. The "Network error" prevented me from updating a post I had written for months because I couldn't figure out why my edits (which extended the length and which I assumed was the problem) couldn't get through.
Trying to contact support was difficult too due to AI chatbots, but when I finally did reach a human, their "tech support" obviously didn't bother to look at this in any reasonable timeframe.
It wasn't until some random person on Twitter suggested the possibility of some magic string tripping over some stupid security logic that I found the problem and could finally edit my post.