title: failed to open the x11 display : unable to connect
body: <p>The server that supports the graphical display is different from the server I'm sshed into. When I try to open virtualbox, I get this message.</p>
  
  <pre><code>$ Failed to open the X11 display!  
  </code></pre>
  
  <p>When I try to startx, I get three error messages.</p>
  
  <pre><code>$ PAM authentication failed, cannot start X server
  
  $ giving up.
  $ xinit:  No such file or directory (errno 2):  unable to connect to X server
  $ xinit:  No such process (errno 3):  Server error.
  </code></pre>
  
  <p>I don't know where the display variable is, as I'm very new to linux.  Any straightforward advice and help would be appreciated.</p>