title: XMPP get error while authentication
body: <p>I am using a xmpppy library to connect with XMPP server... I was able to connect with server but while authentication get error <strong>"Plugging ignored: another instance already plugged."</strong></p>
  
  <p>What does this error mean and how can I resolve it??</p>
  
  <pre><code>In [37]: c.isConnected()
  Out[37]: ''
  
  In [38]: jid = xmpp.protocol.JID('gathole@localhost')
  
  In [39]: c.auth(jid.getNode(),'password', resource=jid.getResource())
  DEBUG: sasl         start Plugging &lt;xmpp.auth.SASL instance at 0x108fc2710&gt; into &lt;xmpp.client.Client instance at 0x109003c68&gt;
  DEBUG: sasl         error Plugging ignored: another instance already plugged.
  Traceback (most recent call last):
    File "/Users/gathole/.virtualenvs/driveu/lib/python2.7/site-packages/IPython/terminal/interactiveshell.py", line 459, in interact
      line = self.raw_input(prompt)
    File "/Users/gathole/.virtualenvs/driveu/lib/python2.7/site-packages/IPython/terminal/interactiveshell.py", line 528, in raw_input
      line = py3compat.cast_unicode_py2(self.raw_input_original(prompt))
  KeyboardInterrupt
  DEBUG: gen_auth     start Plugging &lt;xmpp.auth.NonSASL instance at 0x108fc2710&gt; into &lt;xmpp.client.Client instance at 0x109003c68&gt;
  DEBUG: gen_auth     error Plugging ignored: another instance already plugged.
  Traceback (most recent call last):
    File "/Users/gathole/.virtualenvs/driveu/lib/python2.7/site-packages/IPython/terminal/interactiveshell.py", line 459, in interact
      line = self.raw_input(prompt)
    File "/Users/gathole/.virtualenvs/driveu/lib/python2.7/site-packages/IPython/terminal/interactiveshell.py", line 528, in raw_input
      line = py3compat.cast_unicode_py2(self.raw_input_original(prompt))
  KeyboardInterrupt
  </code></pre>