Avamar SQL cluster backup is failing with error: Unable to connect to the remote client

Avamar SQL backup of dual-homed AlwaysON cluster is failing.

From the main avsql plug-in log:

2017/01/26-11:46:01.41899 [avsql_assist]  avsql_iac_manager::forward_ctl_message() received response dequeued_ret    on queue remote
2017-01-26 12:46:01 avsql Error <0000>: Unable to connect to the remote client '10.x.x.22', error code: 2.
Please ensure that the remote backup agent is running.
2017/01/26-11:46:01.41899 [avsql_assist]  <=== avsql_iac_manager::forward_ctl_message
2017-01-26 12:46:01 avsql Error <12758>: [<Cluster-Client-name>] is unable to forward CTL sub-workorder to [<SQL-SRV-name\instance-name>].
2017/01/26-11:46:01.41899 [avsql_assist]  ===> avsql_iac_manager::update_client_status
2017-01-26 12:46:01 avsql Info <17370>: Remote client: <SQL-SRV-name\instance-name> (10.x.x.22), Status: FAILED
From remote client avagent log we don't see any sub-workorder as the IP in question (10.x.x.22) cannot be contacted from backup IP of AlwaysON listener (10.x.x.81):

initiator_agent_ip="10.x.x.81"
remote_agent_ip="10.x.x.22"

For dual-homed AlwaysON SQL Cluster environment, the SQL nodes Fully Qualified Domain Name (FQDN) is resolved to the IP address from the production network. This network does no have access to the backup network.

This issue can be seen on multi-NIC environments or where there are different vLANs involved.

Permanent resolution:
Upgrade the Avamar Server to.

• 19.7.100-82 or later
• The fix is incorporated in Avamar 19.7 and later software releases.
  • New flag in the avsql.cmd file in the AlwaysON shared VAR:

    • --clusternode=<SQL_node_name>(<IP_ADDRESS>)