NDB API: ndb_ndbapi_simple can't connect (no replies)

I have a working cluster built as follows:
+--------+----------+-------+---------+-----------+---------+
| NodeId | Process | Host | Status | Nodegroup | Package |
+--------+----------+-------+---------+-----------+---------+
| 49 | ndb_mgmd | ndb03 | running | | 7.4.4 |
| 51 | ndb_mgmd | ndb05 | running | | 7.4.4 |
| 53 | ndb_mgmd | ndb04 | running | | 7.4.4 |
| 55 | ndb_mgmd | ndb06 | running | | 7.4.4 |
| 1 | ndbd | ndb03 | running | 0 | 7.4.4 |
| 2 | ndbd | ndb05 | running | 0 | 7.4.4 |
| 3 | ndbd | ndb04 | running | 1 | 7.4.4 |
| 4 | ndbd | ndb06 | running | 1 | 7.4.4 |
| 50 | mysqld | ndb03 | running | | 7.4.4 |
| 52 | mysqld | ndb05 | running | | 7.4.4 |
| 54 | mysqld | ndb04 | running | | 7.4.4 |
| 56 | mysqld | ndb06 | running | | 7.4.4 |
+--------+----------+-------+---------+-----------+---------+

I built the API examples
when I run:
[bobp@ndb03 ndbapi-examples]$ ./ndb_ndbapi_simple ndb03 ndb03
Cluster management server was not ready within 30 secs.

What is the correct connection syntax?