Update the security mechanisms that allow the Agent to communicate with its Advisor.
You might need to update the Agent's host_connection statement to point to the Advisor running in its subplex, and the Advisor's agent_id_list statement to allow a connection from this Agent.
If you are using AT-TLS for security, see Enabling TLS/SSL for ADNR and Enabling TLS/SSL for z/OS Load Balancing Advisor (optional).