VDDK Error: 14009: The server refused connection

I have a Networker 9.2.1 with a vproxy on vmware6. I am trying to do a nbd backup on a different esx where the vproxy is installed. The backup of another VM on the esx where the vproxy is, works without issue.

I already check the port 902 (telnet) from the vproxyVM to the ESX host and it works. the nslookup too.