title: Qt Session management error with matplotlib.pyplot.plot
body: <p>All of a sudden, whenever I call <code>matplotlib.pyplot.plot</code> (within a <code>unix</code> OS), the following error is printed to the screen:</p>
  
  <pre><code>Qt: Session management error: Authentication Rejected, reason : None of the authentication protocols specified are supported and host-based authentication failed
  </code></pre>
  
  <p>This error does not interrupt the function; the plot is created successfully.  But what does this error mean?  </p>
  
  <p>A user on <a href="http://www.linuxforums.org/forum/programming-scripting/148883-solved-session-management-error-authentication-rejected.html" rel="nofollow"><code>linuxforums.org</code></a> was able to find a way to prevent the error:</p>
  
  <p>"I don't know exactly why, but giving permissions to the user in the sudoers file, and then running the program with the <code>sudo</code> command, fixes the error."</p>
  
  <p>This, however, leaves unresolved the cause of the error and whether it influences at all the ongoing process.  </p>
  
  <p>Is there a solution that doesn't require editing the sudoers file?</p>
  
  <p>NB: I'm doing this work on a shared computing cluster.</p>