title: sqldeveloper error message: Network adapter could not establish the connection error
body: <p>I had made connection to the remote Oracle database through SQLDeveloper on my system. Suddenly, the power went down and I had to restart the system.</p>
  <p>Now, when I am trying to connect to the remote oracle database, it's throwing an error message:</p>
  <blockquote>
  <p>The Network adapter could not establish the connection.</p>
  <p>Vendor code 20</p>
  </blockquote>
  <p>Can anyone help me solving this problem?</p>