I just did a fresh instal of the latest WP version. (downloaded it, expanded it and uploaded it via sftp.
If I go to Menu Settings in the administrator page I get the 404 page of my provider. All tabs work except for general one.
Same for Menu Appearance, here I can not access the tab Themes.
I did a 2nd and 3rd new install in the hope it would solve it and the same fault happiness.