when I list domains:
and try to display VNC port for any running VM except Dom0
I get the following error:
I have tried it several times with different VMs on different XenServers but the result is the same.
You can duplicate the error by 1) listing domains:
and then 2) trying to display corresponding VNC port (replace ID with an ID of a running VM)
The command works successfully for the Dom0 only: