Configure an EJB client and the clustered servers if multiple clusters with different applications are used from one client in EAP 6 or EAP 7

Issue

• An EJB client need to talk to different applications deployed in different EAP clusters at the same time, is there a special configuration needed?
• What configuration change is needed if a client invoke EJB's deployed in different EAP clusters
• A client connected to more than one cluster fail occationally if an EJB is called but sometimes the access is successful. The clusters contain different applications.
• Client show messages like below, what it the reason for this?

INFO  [org.jboss.ejb.client.remoting.RemotingConnectionClusterNodeManager] Could not create a connection for cluster node ClusterNode{clusterName='ejb', nodeName='CLUSTER1_NODE1', clientMappings=[ClientMapping{sourceNetworkAddress=/0:0:0:0:0:0:0:0, sourceNetworkMaskBits=0, destinationAddress='192.168.8.27', destinationPort=4447}], resolvedDestination=[Destination address=192.168.8.27, destination port=4447]} in cluster ejb: javax.security.sasl.SaslException: Authentication failed: the server presented no authentication mechanisms