Install updates Pub Key

[triwiwer]

I tried the method on other tread, but i still get error.


===========================
Install Updates Error log
===========================
Install Updates could not fetch the package cache information lists.
Go to https://www.linuxliteos.com/forums/ and paste the log below into a new or existing thread for assistance.

============ Log ===========

Err:1 http://us.old-releases.ubuntu.com/ubuntu focal InRelease
  Could not resolve 'us.old-releases.ubuntu.com'
Err:2 http://us.old-releases.ubuntu.com/ubuntu focal-updates InRelease
  Could not resolve 'us.old-releases.ubuntu.com'
Err:3 http://us.old-releases.ubuntu.com/ubuntu focal-backports InRelease
  Could not resolve 'us.old-releases.ubuntu.com'
Hit:5 https://linux.teamviewer.com/deb stable InRelease
Hit:6 https://brave-browser-apt-release.s3.brave.com stable InRelease
Hit:7 http://archive.canonical.com/ubuntu focal InRelease
Ign:8 http://old-releases.ubuntu.com/ubuntu focal-security InRelease
Hit:9 http://repo.linuxliteos.com/linuxlite emerald InRelease
Get:4 https://www.duinsoft.nl/pkg debs InRelease [12,7 kB]
Err:10 http://old-releases.ubuntu.com/ubuntu focal-security Release
  404  Not Found [IP: 91.189.91.124 80]
Err:4 https://www.duinsoft.nl/pkg debs InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E18CE6625CB26B26
Reading package lists...
E: The repository 'http://old-releases.ubuntu.com/ubuntu focal-security Release' does not have a Release file.
W: GPG error: https://www.duinsoft.nl/pkg debs InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E18CE6625CB26B26
E: The repository 'http://www.duinsoft.nl/pkg debs InRelease' is not signed.
W: Target Packages (all/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list:55 and /etc/apt/sources.list:56
W: Target Packages (all/binary-i386/Packages) is configured multiple times in /etc/apt/sources.list:55 and /etc/apt/sources.list:56
W: Target Packages (all/binary-all/Packages) is configured multiple times in /etc/apt/sources.list:55 and /etc/apt/sources.list:56
W: Target Translations (all/i18n/Translation-en_US) is configured multiple times in /etc/apt/sources.list:55 and /etc/apt/sources.list:56
W: Target Translations (all/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list:55 and /etc/apt/sources.list:56
W: Target CNF (all/cnf/Commands-amd64) is configured multiple times in /etc/apt/sources.list:55 and /etc/apt/sources.list:56
W: Target CNF (all/cnf/Commands-all) is configured multiple times in /etc/apt/sources.list:55 and /etc/apt/sources.list:56