All spinners in vmExplorer dashboard show grayed out for the monitored VC however the corresponding VMware Performance agent status shows that Date/Time stamp for each of the individual collection by the agent is up to date. Investigating further in FglAM Support bundle, below Warning is repeatedly logged in FglAM log:
WARN [Quartz[0]-6/vm-svcrequest-retrievePropertiesEx(id=67)] com.quest.glue.core.util.StdErrOutputStream - [STDERR] java.lang.ClassNotFoundException: com.vmware.vim25.PerfCounterInfoInt
Our agent requests set of counters supported by the VC. It is returning an XML response containing an invalid type (com.vmware.vim25.PerfCounterInfoInt) which is causing the 3rd party library (vijava) to fail to parse the counters. Without the counter names we cannot process and submit the counter values. PerfCounterInfoInt is an internal type, not part of the VC interface.
When the agent starts it requests the list of available counters from the VC. This list contains the ID and Name of each counter. Performance metric requests returns the counter ID only, so we require the ID->Name mapping in order to map each metric to our topology.
This seems to be a VMware bug where they are returning elements other than ones defined in their SOAP interface. Restart of the VC helps probably by re-initializing their data structures which hold the list of available counters.