I am getting this weird error when I'm trying to execute apt update on linux mint. Any recommendations how i can fix this?
Reading package lists... Done E: The repository 'http://www.sourceslist.eu/repo/ubuntu lucid Release' is not signed. 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.
This is my sources.list
#deb cdrom:[Linux Mint 19.1 _Tessa_ - Release amd64 20181217]/ bionic contrib main non-free deb http://www.sourceslist.eu/repo/ubuntu lucid main non-free