moby: 'https://apt.dockerproject.org/repo ubuntu-xenial Release' does not have a Release file

Description

Following the install instructions , I cannot get passed the apt-get updatestep. The update consistently fail with this error: W: The repository 'https://apt.dockerproject.org/repo ubuntu-xenial Release' does not have a Release file.

Here is the relevant part of the output. Notice bad header line.

Ign:11 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
Ign:12 https://apt.dockerproject.org/repo ubuntu-xenial/main all Packages
Ign:13 https://apt.dockerproject.org/repo ubuntu-xenial/main Translation-en
Ign:11 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
Ign:12 https://apt.dockerproject.org/repo ubuntu-xenial/main all Packages
Ign:13 https://apt.dockerproject.org/repo ubuntu-xenial/main Translation-en
Ign:11 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
Ign:12 https://apt.dockerproject.org/repo ubuntu-xenial/main all Packages
Ign:13 https://apt.dockerproject.org/repo ubuntu-xenial/main Translation-en
Ign:11 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
Ign:12 https://apt.dockerproject.org/repo ubuntu-xenial/main all Packages
Ign:13 https://apt.dockerproject.org/repo ubuntu-xenial/main Translation-en
Ign:11 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
Ign:12 https://apt.dockerproject.org/repo ubuntu-xenial/main all Packages
Ign:13 https://apt.dockerproject.org/repo ubuntu-xenial/main Translation-en
Err:11 https://apt.dockerproject.org/repo ubuntu-xenial/main amd64 Packages
  Bad header line
Ign:12 https://apt.dockerproject.org/repo ubuntu-xenial/main all Packages
Ign:13 https://apt.dockerproject.org/repo ubuntu-xenial/main Translation-en
Reading package lists... Done
W: The repository 'https://apt.dockerproject.org/repo 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.dockerproject.org/repo/dists/ubuntu-xenial/main/binary-amd64/Packages  Bad header line
E: Some index files failed to download. They have been ignored, or old ones used instead.

I’ve spent hours crawling through the other similar issues online, nothing helped. The part that is unique to my issue, from what I’ve seen online, is the “bad header line” part

I’ve tried on fresh Aliyun Ubuntu 14.04 and 16.04 instances. All yield the same results.