title: Docker Repository Does Not Have a Release File on Running apt-get update on Ubuntu
body: <p>I am using Ubuntu 16.10 and recently installed Docker (v1.12.4) using the Xenial build by following the instructions found <a href="https://docs.docker.com/engine/installation/linux/ubuntulinux/" rel="noreferrer">here</a>. I haven't encountered any problems creating containers, ensuring they restart automatically, etc.</p>
  
  <p>However, now every time I run <strong>apt-get update</strong> I receive the following error message:</p>
  
  <pre><code>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
  E: Some index files failed to download. They have been ignored, or old ones used instead.
  </code></pre>
  
  <p>I have tried to remedy the problem by following the advice found <a href="https://github.com/docker/docker/issues/22599" rel="noreferrer">here</a> and cannot seem to solve this problem.</p>
  
  <p>Has anyone encountered this before and fixed it? If so, what is needed to resolve this?</p>