Dump Collector Error

i want to configure Dump Collector:

I get this below error when i check the status after enabling and configuring dumpcollector:

esxcli system coredump network check
Error: Unknown command or namespace system coredump network check

Can this happen if the port is blocked ??

when i run the command  "esxcli system coredump network get" i get the output  as below

enabled : true

Host VNic: vmk0
Ntwork Server IP:  192.162.25.61
Network Server Port: 6500

Please suggest

I cannot see  port number "6500" in the list when i run below command..

esxcli network ip connection list