Unable to save profile (another one)

When I edit my profile, I can't change my avatar image, it gives an error:


This error ocurrs when I try to "Upload and user image" or "Use selected image", in both sections, use my own image or select an avatar from an image list.

In the same way, I can't change anythink in my profile... when I push "Save profile", always appears a message on top right:

And nothing has been saved.

I've tried with Chrome, Chromium, Firefox and Edge.