Ign:5 https://esm.ubuntu.com/ubuntu precise InRelease
Err:6 https://esm.ubuntu.com/ubuntu precise Release
[...]
E: The repository 'https://esm.ubuntu.com/ubuntu precise 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.
Behavior on xenial is even worse:
Ign:5 https:/ /esm.ubuntu. com/ubuntu precise InRelease /esm.ubuntu. com/ubuntu precise Release /esm.ubuntu. com/ubuntu precise Release' does not have a Release file.
Err:6 https:/
[...]
E: The repository 'https:/
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.