What git hash and theme? Looks like the same issue here https://community.nodebb.org/post/56422
Edit Post doesn't work in v1.7.5
Editing Posts doesn't work in nodebb v1.7.5
Edit: I just edited your post on v1.7.5 - @pitaj
@PitaJ i have downgraded to v1.7.4 and now it works fine.
v1.7.5 doesn't work for me.
there is a nodebb-popup after press save at the bottom of the page with "... lost connection to nodebb..." every time i try to save. The popup hides to fast to read it complete or take a screenshot. I use multiple ports in my config.json and nginx.
with v1.7.4 everything works fine.
@andreas-pcw can you look in the log for errors?