Support advises to Disable the Optional Service "Enable Consolidation of Job Summary" as it uses a lot of CPU and Network resources in large environments and forces to have the traffic opened from UVMS server to the CDJ port of the DUAS nodes.
In order to do so, go to UVMS - Node Settings - Optional Services:
Enable Consolidation of Job Summary -> No
<Please see attached file for image>
Then Save and restart the UVMS to take into account the modification.
In case you need to have the Service Enabled and the Errors keep appearing in the uvserver.log, the reason behind it is that:
a) either the CDJ server of those nodes is stopped in the given area
b) the nodes are not correctly registered in the UVMS
c) the traffic is closed between UVMS and the CDJ port of those servers