Question regarding federated zones and VNC


in our environment there are several federated zones and VNC is working just fine through the main frontend. However accessing directly a frontend on any location and trying to use the VNC returns error as if the noVNC service is not running. My question is can be noVNC configured to work in both scenarios - from main frontend and from specific’s location frontend

Versions of the related components and OS (frontend, hypervisors, VMs):
centos 7 (latest repo packages) using opennebula 5.10
Steps to reproduce:

Current results:

Expected results: