suslikk, ~ sudo apt update
Hit:1 http://archive.ubuntu.com/ubuntu focal InRelease
Ign:2 http://ppa.launchpad.net/atareao/flameshot/ubuntu focal InRelease
Hit:3 https://deb.nodesource.com/node_12.x focal InRelease
Ign:4 http://dl.google.com/linux/chrome/deb stable InRelease
Get:5 http://archive.ubuntu.com/ubuntu focal-updates InRelease [107 kB]
Hit:6 http://dl.google.com/linux/chrome/deb stable Release
Ign:7 http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu focal InRelease
Hit:9 http://ppa.launchpad.net/linuxuprising/shutter/ubuntu focal InRelease
Get:10 http://archive.ubuntu.com/ubuntu focal-backports InRelease [98,3 kB]
Hit:11 http://ppa.launchpad.net/papirus/papirus/ubuntu focal InRelease
Get:12 http://archive.ubuntu.com/ubuntu focal-security InRelease [107 kB]
Hit:13 http://ppa.launchpad.net/qbittorrent-team/qbittorrent-stable/ubuntu focal InRelease
Ign:14 http://ppa.launchpad.net/snwh/ppa/ubuntu focal InRelease
Hit:15 http://ppa.launchpad.net/starws-box/deadbeef-player/ubuntu focal InRelease
Err:16 http://ppa.launchpad.net/atareao/flameshot/ubuntu focal Release
404 Not Found [IP: 91.189.95.83 80]
Err:17 http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu focal Release
404 Not Found [IP: 91.189.95.83 80]
Err:18 http://ppa.launchpad.net/snwh/ppa/ubuntu focal Release
404 Not Found [IP: 91.189.95.83 80]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/atareao/flameshot/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.
E: The repository 'http://ppa.launchpad.net/danielrichter2007/grub-customizer/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.
E: The repository 'http://ppa.launchpad.net/snwh/ppa/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.