Install Updates could not fetch the package cache information lists.

[Billy and Red]

===========================
Install Updates Error log
===========================
Install Updates could not fetch the package cache information lists.
Go to https://www.freecinema2022.gq/forums/ and paste the log below into a new or existing thread for assistance.

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

Hit:1 http://archive.canonical.com/ubuntu jammy InRelease
Hit:2 http://archive.ubuntu.com/ubuntu jammy InRelease
Hit:3 http://archive.ubuntu.com/ubuntu jammy-updates InRelease
Hit:4 https://dl.google.com/linux/chrome/deb stable InRelease
Hit:5 http://repo.linuxliteos.com/linuxlite fluorite InRelease
Get:6 http://archive.ubuntu.com/ubuntu jammy-backports InRelease [108 kB]
Hit:7 http://security.ubuntu.com/ubuntu jammy-security InRelease
Get:8 https://duinsoft.nl/pkg debs InRelease [6,862 B]
Hit:9 http://archive.ubuntu.com/ubuntu jammy-security InRelease
Err:8 https://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...
W: GPG error: https://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 'https://duinsoft.nl/pkg debs InRelease' is not signed.