Docker Repository Does Not Have a Release File on Running apt-get update on Ubuntu

I am using Ubuntu 16.10 and recently installed Docker (v1.12.4) using the Xenial build by following the instructions found [here][1]. I haven't encountered any problems creating containers, ensuring they restart automatically, etc. However, now every time I run **apt-get update** I receive the following error message: 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. I have tried to remedy the problem by following the advice found [here][2] and cannot seem to solve this problem. Has anyone encountered this before and fixed it? If so, what is needed to resolve this? [1]: https://docs.docker.com/engine/installation/linux/ubuntulinux/ [2]: https://github.com/docker/docker/issues/22599