title: jenkins cannot read from remote repository
body: <p>this is my pipeline script:</p>
  
  <pre><code>pipeline {
      agent any
      stages {
        stage('MVD python') {
            steps {
                git url: 'ssh://git@git.rocketsoftware.com:7999/lg6/mvdzos.git',
                    credentialsId: 'edawes',
                    branch: 'master'
  
                sh 'ls -l'
             }
        }
      }
  }
  </code></pre>
  
  <p>simply trying to test if i can get access to the repo however I am getting the error </p>
  
  <p>Fetching upstream changes from ssh://git@git.rocketsoftware.com:7999/lg6/mvdzos.git</p>
  
  <blockquote>
    <p>git --version # timeout=10
    git fetch --tags --progress ssh://git@git.rocketsoftware.com:7999/lg6/mvdzos.git +refs/heads/<em>:refs/remotes/origin/</em>
    ERROR: Error cloning remote repo 'origin'
    hudson.plugins.git.GitException: Command "git fetch --tags --progress ssh://git@git.rocketsoftware.com:7999/lg6/mvdzos.git +refs/heads/<em>:refs/remotes/origin/</em>" returned status code 128:
    stdout: 
    stderr: Host key verification failed.
    fatal: Could not read from remote repository.</p>
  </blockquote>
  
  <p>beyond the obvious access rights issue which I am pretty sure I have, what else could the problem be? </p>