Wildfly 14 + JGroups + Singleton Cluster Not Working

Configured wildfly14 in domain mode(Configured two servers in domain mode). also configured s3_ping for both the servers. Created one application in which I have implemented singleton cluster. Now I start both the servers together using admin console Runtime-> Topology & Start using Server Group. After starts both the server at same time, the singleton cluster running on both the servers. Following are JGroups configuration. <subsystem xmlns= "urn:jboss:domain:jgroups:6.0" > <channels default= "ee" > <channel name= "ee" stack= "tcp" cluster= "app-cluster" /> </channels> <stacks> <stack name= "udp" > <transport type= "UDP" socket-binding= "jgroups-udp" /> <protocol type= "PING" /> <protocol type= "MERGE3" /> <protocol type= "FD_SOCK" /> <protocol type= "FD_ALL" /> <protocol type= "VERIFY_SUSPECT" /> <protocol type= "pbcast.NAKACK2" /> <protocol type= "UNICAST3" /> <protocol type= "pbcast.STABLE" /> <protocol type= "pbcast.GMS" /> <protocol type= "UFC" /> <protocol type= "MFC" /> <protocol type= "FRAG3" /> </stack> <stack name= "tcp" > <transport type= "TCP" socket-binding= "jgroups-tcp" > <property name= "max_bundle_size" > 32k </property> </transport> <protocol type= "org.jgroups.aws.s3.NATIVE_S3_PING" module= "org.jgroups.native-s3-ping" > <property name= "bucket_name" > bucket-name </property> <property name= "region_name" > region-name </property> </protocol> <protocol type= "MERGE3" > <property name= "min_interval" > 60000 </property> <property name= "max_interval" > 90000 </property> </protocol> <protocol type= "FD_SOCK" socket-binding= "jgroups-tcp-fd" /> <protocol type= "FD_ALL" > <property name= "timeout" > 30000 </property> <property name= "interval" > 15000 </property> <property name= "timeout_check_interval" > 30000 </property> </protocol> <protocol type= "VERIFY_SUSPECT" > <property name= "timeout" > 15000 </property> </protocol> <protocol type= "pbcast.NAKACK2" > <property name= "use_mcast_xmit" > false </property> <property name= "use_mcast_xmit_req" > false </property> <property name= "discard_delivered_msgs" > true </property> <property name= "log_discard_msgs" > false </property> <property name= "max_rebroadcast_timeout" > 10000 </property> <property name= "log_not_found_msgs" > false </property> </protocol> <protocol type= "UNICAST3" > <property name= "log_not_found_msgs" > false </property> </protocol> <protocol type= "pbcast.STABLE" > <property name= "stability_delay" > 10000 </property> <property name= "desired_avg_gossip" > 50000 </property> <property name= "max_bytes" > 4M </property> </protocol> <protocol type= "pbcast.GMS" > <property name= "print_local_addr" > true </property> <property name= "join_timeout" > 10000 </property> <property name= "leave_timeout" > 10000 </property> <property name= "view_bundling" > true </property> <property name= "view_ack_collection_timeout" > 10000 </property> <property name= "max_join_attempts" > 10 </property> </protocol> <protocol type= "MFC" /> <protocol type= "FRAG3" > <property name= "frag_size" > 25k </property> </protocol> </stack> </stacks> </subsystem>