Landscape PPA not working 16.04LTS

Question

I am trying to get Landscape On Premise working on my 16.04LTS Server. Following several answers, will not get me there (How do I install Landscape for personal use?)

PPA is added, but after that when I do the apt update, I receive several errors on the PPA not having a Release file and is therefore disabled.

Err:6 http://ppa.launchpad.net/landscape/16.06/ubuntu xenial Release
  Connection failed
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/landscape/16.06/ubuntu xenial 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.

Even if I add the deb and deb-src by hand, the InRelease works, but the Release variant not. Eventhough the files are at the same place and available on the address!

Also, I have done this with the latest 17.03, but with the same errors. With PPA install:

sudo add-apt-repository ppa:landscape/17.03

 More info: https://launchpad.net/~landscape/+archive/ubuntu/17.03
Press [ENTER] to continue or ctrl-c to cancel adding it

gpg: keyring `/tmp/tmpy1r1eyxx/secring.gpg' created
gpg: keyring `/tmp/tmpy1r1eyxx/pubring.gpg' created
gpg: requesting key 4652B4E6 from hkp server keyserver.ubuntu.com
gpg: /tmp/tmpy1r1eyxx/trustdb.gpg: trustdb created
gpg: key 4652B4E6: public key "Launchpad PPA for Landscape" imported
gpg: Total number processed: 1
gpg:               imported: 1  (RSA: 1)
OK

Err:5 http://ppa.launchpad.net/landscape/17.03/ubuntu xenial Release
  Connection failed
Reading package lists... Done
E: The repository 'http://ppa.launchpad.net/landscape/17.03/ubuntu xenial 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.

Any ideas on how to fix this?