MySQL Cluster – How to Resolve Startup Problems

I have installed MySQL Cluster necessary packages and I am now using Auto installer to config the nodes properly. when I try to start the Cluster In Deploy Configuration part, all the nodes (1 management node, 4 data nodes) starts correctly except SQL node and I got below error.

Command `/usr/local/mysql/bin/mysqld --defaults-file=/home/debian/MySQL_Cluster/49/my.cnf', running on 192.168.120.107 exited with 1:
2016-04-03 16:32:49 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
2016-04-03 16:32:49 0 [Note] /usr/local/mysql/bin/mysqld (mysqld 5.6.28-ndb-7.4.10-cluster-gpl) starting as process 11472 ..

you see all the nodes are started. I use the command it recommended with --explicit_defaults_for_timestamp option like below.

 /usr/local/mysql/bin/mysqld --defaults-file=/home/debian/MySQL_Cluster/49/my.cnf  --explicit_defaults_for_timestamp 
2016-04-03 16:42:06 0 [Note] /usr/local/mysql/bin/mysqld (mysqld 5.6.28-ndb-7.4.10-cluster-gpl) starting as process 11503 ...

you can see with --explicit_defaults_for_timestamp option service start correctly but still when I use management node to see the status I see the cluster has a problem see management node :

ndb_mgm> show 
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)] 4 node(s)
id=1    @192.168.120.111  (mysql-5.6.28 ndb-7.4.10, Nodegroup: 0, *)
id=2    @192.168.120.117  (mysql-5.6.28 ndb-7.4.10, Nodegroup: 0)
id=3    @192.168.120.118  (mysql-5.6.28 ndb-7.4.10, Nodegroup: 1)
id=4    @192.168.120.76  (mysql-5.6.28 ndb-7.4.10, Nodegroup: 1)

[ndb_mgmd(MGM)] 1 node(s)
id=50   @192.168.120.79  (mysql-5.6.28 ndb-7.4.10)

[mysqld(API)]   1 node(s)
id=49 (not connected, accepting connect from 192.168.120.107)

as you can see the SQL node still has not been started correctly :

[mysqld(API)]   1 node(s)
id=49 (not connected, accepting connect from 192.168.120.107)

I don't understand the problem.