ok ho interrotto , ho decommentato le linee che mi hai detto, ho eseguito apt-get update ed è tutto ok tranne per queste ultime linee che ti posto:
Err:21
http://deb.debian.org/debian stretch/updates/main amd64 Packages
404 Not Found [IP: 151.101.112.204 80]
Ign:21
http://cdn-fastly.deb.debian.org/debian stretch/updates/main amd64 Packages
Recuperati 44,4 MB in 2min 1s (366 kB/s)
Lettura elenco dei pacchetti... Fatto
W:
http://security.debian.org/dists/stretc ... /InRelease: The key(s) in the keyring /etc/apt/trusted.gpg are ignored as the file is not readable by user '_apt' executing apt-key.
W:
http://deb.debian.org/debian/dists/stre ... /InRelease: The key(s) in the keyring /etc/apt/trusted.gpg are ignored as the file is not readable by user '_apt' executing apt-key.
W:
http://deb.debian.org/debian/dists/stre ... /InRelease: The key(s) in the keyring /etc/apt/trusted.gpg are ignored as the file is not readable by user '_apt' executing apt-key.
W: The repository 'http://deb.debian.org/debian stretch/updates Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W:
http://deb.debian.org/debian/dists/stre ... /InRelease: The key(s) in the keyring /etc/apt/trusted.gpg are ignored as the file is not readable by user '_apt' executing apt-key.
W:
http://deb.debian.org/debian/dists/stretch/Release.gpg: The key(s) in the keyring /etc/apt/trusted.gpg are ignored as the file is not readable by user '_apt' executing apt-key.
E: Impossibile recuperare
http://deb.debian.org/debian/dists/stre ... 4/Packages 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... slation-en 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... tion-it_IT 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... slation-it 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... -amd64.yml 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... ts-all.yml 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... -64x64.tar 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... 28x128.tar 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... l/Packages 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... 4/Packages 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile recuperare
http://cdn-fastly.deb.debian.org/debian ... slation-it 404 Not Found [IP: 151.101.112.204 80]
E: Impossibile scaricare alcuni file di indice: saranno ignorati o verranno usati quelli vecchi.