Xenstore assigns no vnc-port (xenstore-read: couldn't read path /local/domain/XX/console/vnc-port)

when I list domains:

# list_domains
id | uuid | state
0 | c5c40f42-1d2c-4937-8c1a-7f67c5cac3a9 | R
1 | 5d68eb8c-99a9-a30f-b5ba-8a4fc78bfb35 | RH

and try to display VNC port for any running VM except Dom0

# xenstore-read /local/domain/1/console/vnc-port

I get the following error:

xenstore-read: couldn't read path /local/domain/1/console/vnc-port

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:

# list_domains

and then 2) trying to display corresponding VNC port (replace ID with an ID of a running VM)

# xenstore-read /local/domain/ID/console/vnc-port

The command works successfully for the Dom0 only:

# xenstore-read /local/domain/0/console/vnc-port
5900