The server refuses a request to start a server to server session because a server name is not defined in the server database, or the server definition does not have a SERVERPASSWORD. Server to server communications using the serverpassword requires that the each server has had a server definition for the other server.
Server operation continues.
Register the server names on both servers before establishing a session, or update the server's existing server definition and set a SERVERPASSWORD. An authorized administrator must use the DEFINE SERVER or UPDATE SERVER command register the servers and set the passwords.