Not able to connect to Neptue using java error : java.lang.RuntimeException: java.lang.RuntimeException: org.apache.tinkerpop.gremlin.driver.exception.NoHostAvailableException: All hosts are considered unavailable due to previous exceptions. Check the error log to find the actual reason. at org.apache.tinkerpop.gremlin.process.remote.traversal.step.map.RemoteStep.promise(RemoteStep.java:98)

If i enable iam authentication to neptune , its timing out with exception .
I followed the https://github.com/aws/amazon-neptune-gremlin-java-sigv4/blob/master/src/main/java/com/amazon/neptune/gremlin/driver/example/NeptuneGremlinSigV4Example.java same example

Here is the full log

Successfully loaded SigV4 properties from provider:
Exception in thread "main" java.lang.IllegalStateException: org.apache.tinkerpop.gremlin.process.remote.RemoteConnectionException: java.lang.RuntimeException: java.lang.RuntimeException: org.apache.tinkerpop.gremlin.driver.exception.NoHostAvailableException: All hosts are considered unavailable due to previous exceptions. Check the error log to find the actual reason.
at org.apache.tinkerpop.gremlin.process.remote.traversal.step.map.RemoteStep.promise(RemoteStep.java:98)
at org.apache.tinkerpop.gremlin.process.remote.traversal.step.map.RemoteStep.processNextStart(RemoteStep.java:65)
at org.apache.tinkerpop.gremlin.process.traversal.step.util.AbstractStep.hasNext(AbstractStep.java:144)
at org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal.hasNext(DefaultTraversal.java:196)
at com.amazon.neptune.gremlin.driver.example.NeptuneGremlinSigV4Example.main(NeptuneGremlinSigV4Example.java:104)
Caused by: org.apache.tinkerpop.gremlin.process.remote.RemoteConnectionException: java.lang.RuntimeException: java.lang.RuntimeException: org.apache.tinkerpop.gremlin.driver.exception.NoHostAvailableException: All hosts are considered unavailable due to previous exceptions. Check the error log to find the actual reason.
at org.apache.tinkerpop.gremlin.driver.remote.DriverRemoteConnection.submitAsync(DriverRemoteConnection.java:227)
at org.apache.tinkerpop.gremlin.process.remote.traversal.step.map.RemoteStep.promise(RemoteStep.java:89)
... 4 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: org.apache.tinkerpop.gremlin.driver.exception.NoHostAvailableException: All hosts are considered unavailable due to previous exceptions. Check the error log to find the actual reason.
at org.apache.tinkerpop.gremlin.driver.Client$AliasClusteredClient.submitAsync(Client.java:598)
at org.apache.tinkerpop.gremlin.driver.remote.DriverRemoteConnection.submitAsync(DriverRemoteConnection.java:225)
... 5 more
Caused by: java.lang.RuntimeException: org.apache.tinkerpop.gremlin.driver.exception.NoHostAvailableException: All hosts are considered unavailable due to previous exceptions. Check the error log to find the actual reason.
at org.apache.tinkerpop.gremlin.driver.Client.submitAsync(Client.java:382)
at org.apache.tinkerpop.gremlin.driver.Client$AliasClusteredClient.submitAsync(Client.java:616)
at org.apache.tinkerpop.gremlin.driver.Client$AliasClusteredClient.submitAsync(Client.java:596)
... 6 more
Caused by: org.apache.tinkerpop.gremlin.driver.exception.NoHostAvailableException: All hosts are considered unavailable due to previous exceptions. Check the error log to find the actual reason.

Start with the IAM-enabled connection setup in src/main/java/com/amazon/neptune/gremlin/driver/example/NeptuneGremlinSigV4Example.java and the failing traversal at line 104. Reproduce the timeout and inspect the connection error beneath NoHostAvailableException; done means the example connects to Neptune with IAM authentication without timing out.

Written by the indexing model from the issue text.