Hit:1 http://archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://archive.ubuntu.com/ubuntu focal-updates InRelease
Ign:3 http://ppa.launchpad.net/screenlets/ppa/ubuntu bionic InRelease
Hit:4 http://archive.canonical.com/ubuntu focal InRelease
Hit:5 http://archive.ubuntu.com/ubuntu focal-security InRelease
Get:6 http://security.ubuntu.com/ubuntu xenial-security InRelease [109 kB]
Get:7 http://archive.ubuntu.com/ubuntu xenial-updates InRelease [109 kB]
Err:8 http://ppa.launchpad.net/screenlets/ppa/ubuntu bionic Release
  404  Not Found [IP: 2001:67c:1560:8008::15 80]
Hit:9 http://archive.ubuntu.com/ubuntu focal-backports InRelease
Get:10 http://security.ubuntu.com/ubuntu focal-security InRelease [107 kB]
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/screenlets/ppa/ubuntu bionic 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.