Renaming the nsrladb folder that is inside the res folder is never recommend. Bring back the old and delete the peer information again, this should help. 
Hi all, I was checking out my configuration of Networker Server Client when I discover the Microsoft Exchange Server is missing on the Client Backup Configuration. When I testing to run configure new client for all of the DAG Client, None of the DAG member client have the Microsoft Exchange Server selection on the Available Application column. The backup is already running and there is no failure in backup and restoration testing during the time of discovery of this incident. The only changes so far was a reboot of the Exchange Server that cause the nsrexecd on the primary NMM client to be down ( another reboot to resolve it) and authentication issue ( resolved by delete the peer information between client and server  )
Missing Microsoft Exchange Server on Available Application, NW 18.1