VMware Backup Fails with NBD_ERR_NETWORK_CONNECT Error

VMware Backup Fails with NBD_ERR_NETWORK_CONNECT Error

KB ID: 115056  
Cause:
The "NBD_ERR_NETWORK_CONNECT" error occurs when the ESXi/vCenter network experiences instability during VMware backup, replication, or recovery while attempting to read the VM’s disk data.
Solution:
Follow these steps to troubleshoot and resolve the issue:
1. Check the nslookup of the ESXi server from the BDRShield agent and vice-versa.
2. Verify if you can telnet to port 902 of the ESXi server from both the BDRShield agent and vCenter.
3. Examine the network connectivity of the ESXi host.
4. Ensure that the TCP ports required for the VMware agent are not blocked. Open the following TCP ports in the hypervisor:
  1. Port 22
  2. Port 80 and 443 (if not customized, use the default ports)
  3. Port 902
Additionally:
Confirm that the datastore (iSCSI, NFS) added to the ESXi host has stable network connectivity from the host.
If the issue persists despite the above steps, please contact BDRShield support, providing the backup log and vSphere log of the job for further assistance.