title: How to resolve the below error
body: <pre><code>Enter user-name: xl_dba@test
  Enter password:
  </code></pre>
  
  <blockquote>
    <p>ERROR: ORA-12528: TNS:listener: all appropriate instances are blocking new `</p>
  </blockquote>
  
  <p>How to resolve that error?</p>