@virasana The transport error regards the DN of the node’s certificate. Starting from version 2.0, transport client authentication/authorization has been deprecated.
You need to specify a list of nodes DNs in the opensearch.yml
plugins.security.nodes_dn(Static): Specifies a list of distinguished names (DNs) that denote the other nodes in the cluster. This setting supports wildcards and regular expressions. The list of DNs are also read from the security index in addition to the YAML configuration whenplugins.security.nodes_dn_dynamic_config_enabledistrue. If this setting is not configured correctly, the cluster will fail to form as the nodes will not be able to trust each other and will result in the following error:Transport client authentication no longer supported.
Try adding this option to config.plugins.security.nodes_dn in values.yml