I think the problem is a denial of access to the theme data while the UNIX permissions of the wp-content folder are set to RW for user and R for the other two.
The point is I tried to set the CMOD for the wp-content folder for user rwx.
This is not the problem because I returned it to the previous setting.
My problem is that that the theme is no longer good. I used to have a banner with Aljo-Log and a sidebar now both are gone. The sidebar in now at the bottom of the screen.
In the presenation section while logged in the themes are no longer good because the pictures for kubrik default and classic are no longer displayed so somewhere data got damaged.
I hope it is now clearer what my problem is.