NetWorker: Cloning failed for all VMware save sets, when Retention Lock is enabled on mtree

The NetWorker server's daemon.raw reports:

21.05.2025 14:33:02  nsrvproxy_save NSR notice Action backup vmware-vproxy '01_Backup_A' has initialized as 'vproxysave job' with job id 37468067
... <-- backup runtime ~1 min
21.05.2025 14:34:11  nsrvproxy_save NSR notice Action backup vmware-vproxy '01_Backup_A' with job id 37468067 is exiting with status 'succeeded', exit code 0

21.05.2025 14:34:17  nsrclone NSR notice Action clone '02_Clone_A' has initialized as 'clone job' with job id 37468071
... <-- clone runtime (~10 min.) > backup time (~1 min.), which indicates CCR is not working
21.05.2025 14:45:09  nsrclone NSR notice Action clone '02_Clone_A' with job id 37468071 is exiting with status 'failed', exit code 1

• Linux: /nsr/logs/daemon.raw
• Windows (Default): C:\Program Files\EMC NetWorker\nsr\logs\daemon.raw

The Clone action log reports the following failures.

0 1747830885 1 9 0 20384 12292 0 server.abc.local nsrclone JOBS notice 2 %s 1 0 80 180221:nsrrecopy: Job ID 37468073: Adding new work item '1965934607/1747830799'.
0 1747830916 1 9 0 20384 12292 0 server.abc.local nsrclone JOBS notice 2 %s 1 0 73 202332:nsrrecopy: Unable to obtain the synthetic replication information.
0 1747830979 1 9 0 20384 12292 0 server.abc.local nsrclone JOBS notice 2 %s 1 0 73 202332:nsrrecopy: Unable to obtain the synthetic replication information.
...
0 1747831494 1 9 0 20384 12292 0 server.abc.local nsrclone JOBS notice 2 %s 1 0 406 108651:nsrrecopy: Failed to finish saveset for ss 1965934607 : Retrieving statistics for '/server/abcCloneVM_02/14/67/33faf836-00000006-752dc80f-682dc80f-9b8d5000-ee318156' failed [5004] ([15252] [10316] Wed May 21 14:44:54 2025    ddp_stat() failed, Path server/abcCloneVM_02/14/67/33faf836-00000006-752dc80f-682dc80f-9b8d5000-ee318156, Err: 5004-nfs lookup failed (nfs: No such file or directory)). 
0 1747831494 1 9 0 20384 12292 0 server.abc.local nsrclone JOBS notice 2 %s 1 0 361 107512:nsrmmd #94: Retrieving statistics for '/server/abcCloneVM_02/14/67/33faf836-00000006-752dc80f-682dc80f-9b8d5000-ee318156' failed [5004] ([15252] [10316] Wed May 21 14:44:54 2025    ddp_stat() failed, Path server/abcCloneVM_02/14/67/33faf836-00000006-752dc80f-682dc80f-9b8d5000-ee318156, Err: 5004-nfs lookup failed (nfs: No such file or directory)).
0 1747831494 1 9 0 20384 12292 0 server.abc.local nsrclone JOBS notice 2 %s 1 0 103 181307:nsrrecopy: PID-23884 with job ID 37468073 with recover stream ID 164893: Save session is ending.

Data Domain is configured with more than one Network. For Example:

Management Interface:
veth0 10.2.6.5 

Data Interface:
eth5a 194.11.241.160 
eth5b 194.11.241.161 
 

Source and Target DD are reachable over the Management interface. Route has been set, that Data traffic is moved over Data Interface. Traffic between Mgmt. and Data Interface Port 2051 is blocked.

tcpdump from source DD shows that there is a connection attempt between Mgmt and Data interface to target DD, Port 2051, which is blocked by a firewall.

Keep in mind, this behavior is not seen on non RL enabled mtree.

1667   08:37:14   10.2.6.5 -> 139.0.198.51 TCP 76 [TCP Retransmission] 52488 > 2051 [SYN] Seq=0 Win=65535 Len=0 MSS=1460 SACK_PERM=1 TSval=3741408423 TSecr=0 WS=256
1668   08:37:14   10.2.6.5 -> 139.0.198.51 TCP 76 [TCP Retransmission] 52488 > 2051 [SYN] Seq=0 Win=65535 Len=0 MSS=1460 SACK_PERM=1 TSval=3741408423 TSecr=0 WS=256
3973   08:37:17   10.2.6.5 -> 139.0.198.51 TCP 76 [TCP Retransmission] 52488 > 2051 [SYN] Seq=0 Win=65535 Len=0 MSS=1460 SACK_PERM=1 TSval=3741410472 TSecr=0 WS=256
3974   08:37:17   10.2.6.5 -> 139.0.198.51 TCP 76 [TCP Retransmission] 52488 > 2051 [SYN] Seq=0 Win=65535 Len=0 MSS=1460 SACK_PERM=1 TSval=3741410472 TSecr=0 WS=256

Add an additional route on the source DD:

route add net NETWORK_IP_ADDRESS netmask SUBNET_MASK gw GATEWAY_IP_ADDRESS NETWORK_ADAPTER_NAME