Validation error while adding VMware credentials to NetBackup

For protecting VMware virtual machines, you add the login credentials of the VMware vCenter Server, VMware ESXi server, or VMware vCloud Director server to the NetBackup configuration. While adding the access credentials, you may see the following credential validation error in the NetBackup Java Console UI.

VMware credential validation failed. Cannot connect on socket (Status 25)

This issue occurs when the NetBackup Flex Scale appliance cluster is configured using a pure IPv6 address configuration while the VMware system uses IPv4 addresses. NetBackup Flex Scale appliance does not support communication between a pure IPv6 and a pure IPv4 address configuration.

To resolve this issue, the VMware system must be configured to use either a pure IPv6 address or a mixed mode dual stack IP address configuration.