in synaptic: Could not download all repository indexes
The repository may no longer be available or could not be contacted because of network problems. If available an older version of the failed index will be used. Otherwise the repository will be ignored. Check your network connection and ensure the repository address in the preferences is correct.
The repository 'http://ppa.launchpad.net/george-edison55/cmake-3.x/ubuntu focal Release' does not have a Release file.
in the terminal:
rinka@ThinkCentre-M91-RINKA:~$ sudo apt-get update && sudo apt-get upgrade
[sudo] password for rinka:
Hit:1 https://repo.steampowered.com/steam stable InRelease
Hit:2 https://repo.steampowered.com/steam beta InRelease
Hit:3 http://archive.canonical.com/ubuntu focal InRelease
Ign:4 http://ppa.launchpad.net/george-edison55/cmake-3.x/ubuntu focal InRelease
Hit:5 http://security.ubuntu.com/ubuntu focal-security InRelease
Hit:6 http://ph.archive.ubuntu.com/ubuntu focal InRelease
Hit:7 http://ph.archive.ubuntu.com/ubuntu focal-updates InRelease
Err:8 http://ppa.launchpad.net/george-edison55/cmake-3.x/ubuntu focal Release
404 Not Found [IP: 91.189.95.85 80]
Get:9 http://ph.archive.ubuntu.com/ubuntu focal-backports InRelease [101 kB]
Hit:10 https://repo.protonvpn.com/debian stable InRelease
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/george-edison55/cmake-3.x/ubuntu focal Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
