Error while creating Exchange Node client. Networker Exchange 2016 IP-Less , NW 18.1

Hi All,

I have 8 DAG Node, 4 each for PROD and 4 for DR

The Prod DAG Node have been install with NMM and NW Client. 18.1 , none on DR.

I noticed the following  while creating the Exchange Client ,

1. While selecting the Preferred Server List, I will see all 8 available server for Federated Backup.

2. I only selected the servers within the PROD site and after the summary is over, during the creation, this error occur

"DR01 is not a know host or trusted domain. Networker cannot validate the identity of these users "

Since I suspect I need to install NMM and NW Client at the DR, I proceed to test install on a DR01.

After installation, I recreate the Client and the same error reoccur. 

After a few retries, going back and create,  the error start with DR1, becomes DR2, DR3 and lastly DR4 before ended up with this error instead

" Adding New Client

- Successfully added new Client PROD01

Create Other client

- Operation Failed

- Name DR1 is not a valid host name as it cannot be resolved in DNS . Please add it to DNS or the hosts file and flush the networker server DNS cache.  

( dbgcommand -p FlushDnsCache )

Undoing any previous Operations

- Rolling Back Adding new Client "PROD1"

- Successfully rolled back client "PROD1"

Thank you in advance!