local apt-mirror says Release cant be found, but its there, what am i missing

Question

running apt-get update on a host thats pointing at my local mirror returns the following warnings and errors...

W: The repository 'https://apt.devita.co/puppet xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: The repository 'https://apt.devita.co/ubuntu xenial-backports Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: The repository 'https://apt.devita.co/ubuntu xenial-security Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: The repository 'https://apt.devita.co/ubuntu xenial-updates Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: The repository 'https://apt.devita.co/ubuntu xenial Release' does not have a Release file.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: Failed to fetch https://apt.devita.co/puppet/dists/xenial/PC1/binary-amd64/Packages
E: Failed to fetch https://apt.devita.co/ubuntu/dists/xenial-backports/main/binary-amd64/Packages
E: Failed to fetch https://apt.devita.co/ubuntu/dists/xenial-security/main/binary-amd64/Packages
E: Failed to fetch https://apt.devita.co/ubuntu/dists/xenial-updates/main/binary-amd64/Packages
E: Failed to fetch https://apt.devita.co/ubuntu/dists/xenial/main/binary-amd64/Packages
E: Some index files failed to download. They have been ignored, or old ones used instead.

you can see screenshots of the local repo here, and the repo is publically available temporarily while I troubleshoot.

my sources.list.d looks like this

# This file is managed by Puppet. DO NOT EDIT.
# puppetlabs-pc1
deb https://apt.devita.co/puppet xenial PC1 main
# This file is managed by Puppet. DO NOT EDIT.
# xenial-backports
deb https://apt.devita.co/ubuntu/ xenial-backports main restricted universe multiverse
# This file is managed by Puppet. DO NOT EDIT.
# xenial
deb https://apt.devita.co/ubuntu/ xenial main restricted universe multiverse
# This file is managed by Puppet. DO NOT EDIT.
# xenial-security
deb https://apt.devita.co/ubuntu/ xenial-security main restricted universe multiverse
# This file is managed by Puppet. DO NOT EDIT.
# xenial-updates
deb https://apt.devita.co/ubuntu/ xenial-updates main restricted universe multiverse

and the /var/www dir is symlinks to the apt-mirror locations like so

Answer 1

We've been discussing this on IRC in #ubuntu-server. So far it looks like a CA added to /etc/ssl/certs broke update-ca-certificates, so /etc/ssl/certs/ca-certificates.crt was broken or just empty, so apt-transport-https wasn't working at all.

Debugged using: apt-get -o Debug::Acquire::https=1 update