If you are sshing to another system, be sure that remote server allows ssh forwarding. Tighter security, it is preferred over ‘ssh -Y’ see the SSH manual. You can forward X11 over an SSH connection by using either ‘ssh -X’ or ‘ssh -Y’. (MacPorts' X11.app) launchctl unload -w /Library/LaunchAgents/ (Apple's X11.app) launchctl unload -w /System/Library/LaunchAgents/org.x.ist
(XQuartz.app 2.7.x and earlier) launchctl unload -w /Library/LaunchAgents/.plist (XQuartz.app 2.8.x and later) launchctl unload -w /Library/LaunchAgents/