server problems 403, file not found

[Ampersand]

maybe you have some htaccess rewrite, make sure you didnt put a htaccess in the wrong place. try a fresh install confirm  working, copy over it to complete, that is the recommended method of moving stuff. make sure you change your site url properly. check health check also.

Yes, I'll try to change .htaccess to default, so far have just commented out what I could, but still no improvement.
Changed pages don't get saved. Server log is now clear, no server errors that I included above.
I consider fresh install, but trying to avoid it for now. For the moment, please have a look at health check, that I have just noticed. All lines are green except for a one. If I understand well, it has warned about the very .htaccess in /data dir?