NetBackup Deduplication Engine service stuck in "starting" mode.

Problem

NetBackup Deduplication Engine service stuck in "starting" mode.

Error Message

spoold logs:
---------------
sessionStartAgent: establishing session with servername-bk:10102 on socket 12470376
January 15 09:14:46 INFO [000002018602A4F0]: sessionStartAgent: using local address servername-bk:60637
January 15 09:14:46 INFO [000002018602A4F0]: sessionStartAgent: Server is Version 13.0001.0020.08, Protocol Version 6.6.1.1.2
January 15 09:14:47 ERR [000002018602A4F0]: 25058: SSL read failed [6]: incorrect packet size '0'
January 15 09:14:47 ERR [000002018602A4F0]: 25058: CRSessionStart: connect to server failed!
January 15 09:14:47 WARNING [000002018602A4F0]: 25058: Failed to get startup CR modes from SPA after 137 attempts, retrying in 10 seconds

Cause

Spoold is trying to establish session with backup NIC servername-bk.

Solution

1. Check the the name resolution with both production IP and backup IP network with the master server. Make the host file entry of Master on media server and vice-versa.
2. Also In NBU console , under Security Management - Host Management, Approve Mappings suggested in 'Mappings for Approval' or Map the Production name with the Backup name and FQDN name of the server manually.