lucaviola73 on "500 - internal server error - can't access admin"

Thanks Matthew, as you can read in my prior message, I'already tryed out everithing you wrote.
Changed theme: broblem not resolved
Disabled plugins via FTP: broblem not resolved
Deleted .htaccess: problem not resolved

So I activated wp log and also server log.
In the first message I've already included the error messages I found in the server and wp logs.

Any suggestion based on the errors registered?

Thanks.

P.S. All the problems are in the admin panel. Something works, something doesn't.
I can't access plugins admin, theme admin, wp updates.
When I publish an article I get 500 internal server error, but the article results published.