Comment 3 for bug 1764060

After the above error happened, I'm getting these on subsequent attempts to do apt-get update / dist-upgrade:

Reading package lists... Done
W: https://repo.skype.com/deb/dists/stable/InRelease: No system certificates available. Try installing ca-certificates.
W: https://repo.skype.com/deb/dists/stable/Release: No system certificates available. Try installing ca-certificates.
E: The repository 'https://repo.skype.com/deb stable Release' no longer has 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.
W: https://download.sublimetext.com/apt/dev/InRelease: No system certificates available. Try installing ca-certificates.
W: http://download.tarantool.org/tarantool/1.7/ubuntu/dists/xenial/InRelease: No system certificates available. Try installing ca-certificates.
W: https://download.sublimetext.com/apt/dev/Release: No system certificates available. Try installing ca-certificates.
E: The repository 'https://download.sublimetext.com apt/dev/ Release' no longer has 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.
W: http://download.tarantool.org/tarantool/1.7/ubuntu/dists/xenial/Release: No system certificates available. Try installing ca-certificates.
E: The repository 'http://download.tarantool.org/tarantool/1.7/ubuntu xenial Release' no longer has 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.