mysqld node not connecting to cluster I'm trying to set up a basic NDB cluster, the data nodes register correctly but the mysqld API node doesn't accept

Connected to Management Server at: 174.138.80.168:1186
Cluster Configuration
---------------------
[ndbd(NDB)]     2 node(s)
id=2    @104.131.16.252  (mysql-5.6.37 ndb-7.4.16, Nodegroup: 0, *)
id=3    @174.138.80.126  (mysql-5.6.37 ndb-7.4.16, Nodegroup: 0)

[ndb_mgmd(MGM)] 1 node(s)
id=1    @174.138.80.168  (mysql-5.6.37 ndb-7.4.16)

[mysqld(API)]   1 node(s)
id=4 (not connected, accepting connect from manager.mysql.cluster)


Manager Node's my.cnf

[ndb_mgmd]
config-dir=/usr/local/mysql/mysql-cluster
config-file=/usr/local/mysql/mysql-cluster/config.ini

# MySQL Config
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
user=mysql

# Run ndb storage engine
ndbcluster
# IP address management node
ndb-connectstring=174.138.80.168

# MySQL Pid and Log
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid


Management Node's /var/lib/mysql-cluster/config.ini file

[ndb_mgmd]
# Management process options:
hostname=manager.mysql.cluster  # Hostname of the manager
[ndbd]
hostname=node1.mysql.cluster    # Hostname of the first data node
datadir=/var/lib/mysql-cluster   # Remote directory for the data files

[ndbd]
hostname=node2.mysql.cluster    # Hostname of the second data node
datadir=/var/lib/mysql-cluster   # Remote directory for the data files

[mysqld]
# SQL node options:
hostname=manager.mysql.cluster


Each of the data node's /etc/my.cnf files:

# MySQL Config
[mysqld]
datadir=/usr/local/mysql/data
socket=/tmp/mysql.sock
user=mysql

# Run ndb storage engine
ndbcluster
# IP address management node
ndb-connectstring=174.138.80.168

[mysql_cluster]
# IP address management node
ndb-connectstring=174.138.80.168

# MySQL Pid and Log
[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid


Thanks
I guess I had that issue before
double check whether mysql has been started or not
run following command and see  

[root@aba ~]# systemctl status mysqld.service  


active status should be 

 Active: active (running) since Wed 2018-02-7 12:50:46  


before set up cluster