I've upgraded today to Jenkins 1.554 and Xvnc plugin 1.16 and the jobs started to fail.

• Xvnc command line (from Jenkins config):

  vncserver :$DISPLAY_NUMBER -nolisten tcp -geometry 1280x800 -depth 24 -fp catalogue:/etc/X11/fontpath.d
  

• Xvnc related info in the job log:

  [xwiki-enterprise-test-extension] $ vncserver :71 -nolisten tcp -geometry 1280x800 -depth 24 -fp catalogue:/etc/X11/fontpath.d
  
  New 'X' desktop is vagent-1-2-dev:71
  
  Starting applications specified in /home/hudsonagent/.vnc/xstartup
  Log file is /home/hudsonagent/.vnc/vagent-1-2-dev:71.log
  
  ...
  
  java.lang.InternalError: Can't connect to X11 window server using ':71' as the value of the DISPLAY variable.
  

• vnc log:

  10/03/14 16:22:14 Xvnc version TightVNC-1.3.9
  10/03/14 16:22:14 Copyright (C) 2000-2007 TightVNC Group
  10/03/14 16:22:14 Copyright (C) 1999 AT&T Laboratories Cambridge
  10/03/14 16:22:14 All Rights Reserved.
  10/03/14 16:22:14 See http://www.tightvnc.com/ for information on TightVNC
  10/03/14 16:22:14 Desktop name 'X' (vagent-1-2-dev:71)
  10/03/14 16:22:14 Protocol versions supported: 3.3, 3.7, 3.8, 3.7t, 3.8t
  10/03/14 16:22:14 Listening for VNC connections on TCP port 5971
  Font directory '/usr/share/fonts/X11/Speedo/' not found - ignoring
  Font directory '/usr/share/fonts/X11/Type1/' not found - ignoring
  Font directory '/usr/share/fonts/X11/75dpi/' not found - ignoring
  Font directory '/usr/share/fonts/X11/100dpi/' not found - ignoring
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  Client is not authorized to connect to Serverxrdb: Resource temporarily unavailable
  xrdb: Can't open display ':71'
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  Client is not authorized to connect to Serverxsetroot:  unable to open display ':71'
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:22:15 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:23:26 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:23:26 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:23:26 2014: 27217 Xtightvnc: client 1 rejected from local host
  AUDIT: Mon Mar 10 16:23:26 2014: 27217 Xtightvnc: client 1 rejected from local host
  

• vnc command line (ps -aux | grep vnc):

  Xtightvnc :71 -desktop X -auth /home/hudsonagent/hudson_root/workspace/xwiki-enterprise-test-extension/.Xauthority-328169632546426497 -geometry 1280x800 -depth 24 -rfbwait 120000 -rfbauth /home/hudsonagent/.vnc/passwd -rfbport 5971 -co /etc/X11/rgb -nolisten tcp
  

• When trying to start the browser from the command line:

  Client is not authorized to connect to ServerClient is not authorized to connect to ServerError: cannot open display: :71
  

Downgrading back to 1.14 version of Xvnc fixed the problem.

Note that I can start the browser (and everything works fine) if I run this:

Xtightvnc :71 -desktop X -auth /home/hudsonagent/.Xauthority -geometry 1280x800 -depth 24 -rfbwait 120000 -rfbauth /home/hudsonagent/.vnc/passwd -rfbport 5971 -co /etc/X11/rgb -nolisten tcp

from the command line instead. Thus it seems the problem is with the

/home/hudsonagent/hudson_root/workspace/xwiki-enterprise-test-extension/.Xauthority-328169632546426497

file or path (although .Xauthority-328169632546426497 seems to be just a copy of .Xauthority, same size).