title: git clone failed from Jenkins: port 443 operation timed out
body: <p>I am running a jenkins pipeline which is having 2 layered git repos.</p>
  <ol>
  <li>Jenkins pipeline is in one repo from which pipeline is triggered.</li>
  <li>once pipeline is triggered it clones repo from another git repo to perform some operations.</li>
  </ol>
  <p>I am able to trigger the pipeline, it starts correctly but give me following error when it starts to perform checkout of another repo-</p>
  <pre><code>fatal: unable to access 'https://github.com/&lt;project-name&gt;/&lt;project&gt;.git/': Failed to connect to github.com port 443: Operation timed out
  [Pipeline] echo
  hudson.AbortException: script returned exit code 128
  </code></pre>
  <p>any help or pointers what is wrong.</p>