Exchange GRT backups completing partially with error ' ERR - Unable to NFS mount the required file system '

Problem

The Exchange GRT backups completing partially.

Error Message

ERR - Unable to NFS mount the required file system

Cause

Name resolution. 

Solution

The issue can be specific to 1 or more nodes 
Logon to the Exchange node in question. 
Make sure that the <install_path>\Veritas\Netbackup\bin> bpclntcmd -pn shows the correct output 

If not, then update the hosts file on the Exchange and master server 

OR 

Update the DNS ( forward and reverse lookup zone ) entries of Master and Exchange server. 

Run <install_path>\Veritas\Netbackup\bin> bpclntcmd -hn command against the media server used for the backup. 
If this shows an incorrect IP address, then perform either of the following: 

Create\update the hosts file entry on the client for the Media server with the correct IP Address. 

OR

Update the DNS ( forward and reverse lookup zone ) entries for the Media server. 

Clear the host cache on media server and the Exchange server using the following command: 

<install_path>\Veritas\Netbackup\bin> bpclntcmd -clear_host_cache