sudo apt-get update
Hit:1 http://us.archive.ubuntu.com/ubuntu jammy InRelease
Hit:2 http://us.archive.ubuntu.com/ubuntu jammy-updates InRelease
Hit:3 http://us.archive.ubuntu.com/ubuntu jammy-backports InRelease
Hit:4 http://security.ubuntu.com/ubuntu jammy-security InRelease
Ign:5 https://ppa.launchpadcontent.net/shutter/ppa/ubuntu jammy InRelease
Err:6 https://ppa.launchpadcontent.net/shutter/ppa/ubuntu jammy Release
404 Not Found [IP: 185.125.190.52 443]
Reading package lists... Done
E: The repository 'https://ppa.launchpadcontent.net/shutter/ppa/ubuntu jammy 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.
See Err:6 above. I tried to do a ppa-purge:
sudo ppa-purge ppa:shutter/ppa
Updating packages lists
E: The repository 'https://ppa.launchpadcontent.net/shutter/ppa/ubuntu jammy Release' does not have a Release file.
Warning: apt-get update failed for some reason
Apparently I'm doing something wrong, but I don't know what it is. Any suggestions are appreciated.