I worked with orionp in #x2go IRC channel and he wanted me to file a bug because we discovered that the /etc/init.d/x2gocleansessions script doesn't seem to: 1) stop properly and 2) doesn't create /tmp/.X11-unix/ After manually killing the process... removing the lock file, and then manually creating the /tmp/.X11-unix/ dir as root.root 1777 I could connect with x2go client. Without that, not so much.
x2goserver-4.0.1.8-1.el6 has been submitted as an update for Fedora EPEL 6. https://admin.fedoraproject.org/updates/x2goserver-4.0.1.8-1.el6
Package x2goserver-4.0.1.8-1.el6: * should fix your issue, * was pushed to the Fedora EPEL 6 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=epel-testing x2goserver-4.0.1.8-1.el6' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-EPEL-2013-12186/x2goserver-4.0.1.8-1.el6 then log in and leave karma (feedback).
x2goserver-4.0.1.8-2.fc20 has been submitted as an update for Fedora 20. https://admin.fedoraproject.org/updates/x2goserver-4.0.1.8-2.fc20
x2goserver-4.0.1.8-2.el6 has been submitted as an update for Fedora EPEL 6. https://admin.fedoraproject.org/updates/x2goserver-4.0.1.8-2.el6
x2goserver-4.0.1.8-2.fc19 has been submitted as an update for Fedora 19. https://admin.fedoraproject.org/updates/x2goserver-4.0.1.8-2.fc19
x2goserver-4.0.1.9-2.el6 has been pushed to the Fedora EPEL 6 stable repository. If problems still persist, please make note of it in this bug report.