title: docker cp throws "No such container:path" on running instance
body: <p>After trying <code>docker cp</code> <a href="https://stackoverflow.com/questions/22049212/copying-files-from-docker-container-to-host/22050116#22050116">from here</a>, it still throws a <code>Error: No such container:path:...</code></p>
  <p><a href="https://i.stack.imgur.com/uXL7U.png" rel="noreferrer"><img src="https://i.stack.imgur.com/uXL7U.png" alt="enter image description here" /></a></p>
  <p>What am I doing wrong?</p>
  <ul>
  <li>The container is running</li>
  <li>I can run <code>docker exec</code> commands</li>
  <li><code>docker cp</code> fails</li>
  </ul>