ERROR WSREP`: gcs/src/gcs.cpp:gcs_open():1379:` Failed to open channel 'test_cluster'

I have three server that I want to Install Galera clustering on them, I followed this [link](https://www.digitalocean.com/community/tutorials/how-to-configure-a-galera-cluster-with-mariadb-on-ubuntu-12-04-servers) to install and config it. but when I want to start the first server I got this error : root@node107:/home/debian# service mysql start --wsrep-new-clusterping Job for mysql.service failed. See 'systemctl status mysql.service' and 'journalctl -xn' for details. and : root@node107:/home/debian# journalctl -xn -- Logs begin at Tue 2016-03-01 19:02:04 IRST, end at Tue 2016-03-01 19:39:32 IRST. -- Mar 01 19:39:31 node107 mysqld: 160301 19:39:31 [ERROR] WSREP: gcs/src/gcs.cpp:gcs_open():1379: Failed to open channel 'test_cluster' at 'gcomm://192.168.120.107,192.168.120.111,192.168.120.11 Mar 01 19:39:31 node107 mysqld: 160301 19:39:31 [ERROR] WSREP: gcs connect failed: Connection timed out Mar 01 19:39:31 node107 mysqld: 160301 19:39:31 [ERROR] WSREP: wsrep::connect(gcomm://192.168.120.107,192.168.120.111,192.168.120.117) failed: 7 Mar 01 19:39:31 node107 mysqld: 160301 19:39:31 [ERROR] Aborting Mar 01 19:39:31 node107 mysqld: Mar 01 19:39:31 node107 mysqld: 160301 19:39:31 [Note] WSREP: Service disconnected. Mar 01 19:39:32 node107 mysqld: 160301 19:39:32 [Note] WSREP: Some threads may fail to exit. Mar 01 19:39:32 node107 mysqld: 160301 19:39:32 [Note] /usr/sbin/mysqld: Shutdown complete Mar 01 19:39:32 node107 mysqld: Mar 01 19:39:32 node107 mysqld_safe: mysqld from pid file /var/run/mysqld/mysqld.pid ended these are configuration file for the three servers : vim /etc/mysql/conf.d/cluster.cnf **Server1 :** [mysqld] query_cache_size=0 binlog_format=ROW default-storage-engine=innodb innodb_autoinc_lock_mode=2 query_cache_type=0 bind-address=0.0.0.0 # Galera Provider Configuration wsrep_provider=/usr/lib/galera/libgalera_smm.so #wsrep_provider_options="gcache.size=32G" # Galera Cluster Configuration wsrep_cluster_name="test_cluster" wsrep_cluster_address="gcomm://192.168.120.107,192.168.120.111,192.168.120.117" #wsrep_cluster_address="gcomm://192.168.120.107" # Galera Synchronization Congifuration wsrep_sst_method=rsync #wsrep_sst_auth=user:pass # Galera Node Configuration wsrep_node_address="192.168.120.107" wsrep_node_name="node107" **Server 2:** [mysqld] query_cache_size=0 binlog_format=ROW default-storage-engine=innodb innodb_autoinc_lock_mode=2 query_cache_type=0 bind-address=0.0.0.0 # Galera Provider Configuration wsrep_provider=/usr/lib/galera/libgalera_smm.so #wsrep_provider_options="gcache.size=32G" # Galera Cluster Configuration wsrep_cluster_name="test_cluster" wsrep_cluster_address="gcomm://192.168.120.107" #wsrep_cluster_address="gcomm://192.168.120.107,192.168.120.111,192.168.120.117" # Galera Synchronization Congifuration wsrep_sst_method=rsync #wsrep_sst_auth=user:pass # Galera Node Configuration wsrep_node_address="192.168.120.111" wsrep_node_name="node111" **server 3 :** [mysqld] query_cache_size=0 binlog_format=ROW default-storage-engine=innodb innodb_autoinc_lock_mode=2 query_cache_type=0 bind-address=0.0.0.0 # Galera Provider Configuration wsrep_provider=/usr/lib/galera/libgalera_smm.so #wsrep_provider_options="gcache.size=32G" # Galera Cluster Configuration wsrep_cluster_name="test_cluster" wsrep_cluster_address="gcomm://192.168.120.107,192.168.120.111,192.168.120.117" # Galera Synchronization Congifuration wsrep_sst_method=rsync #wsrep_sst_auth=user:pass # Galera Node Configuration wsrep_node_address="192.168.120.117" wsrep_node_name="node117" I don't understand what I have missed. what should I do?