Unable to connect Cassandra Cluster in AWS from EC2 instance - amazon-web-services

Question

I setup Cassandra Cluster Using DataStax AMI in AWS and run the cassandra service. I am trying to connect this cassandra service from another EC2 instance where titan is installed. Titan server version is 0.4.4. I also tried with 0.5.3 but still the same error.
Cassandra is backend storage for the titan .
Error is
20366 [main] WARN com.tinkerpop.rexster.config.GraphConfigurationContainer - Could not load graph graph. Please check the XML configuration.
20367 [main] WARN com.tinkerpop.rexster.config.GraphConfigurationContainer - GraphConfiguration could not be found or otherwise instantiated: [com.thinkaurelius.titan.tinkerpop.rexster.TitanGraphConfiguration]. Ensure that it is in Rexster's path.
com.tinkerpop.rexster.config.GraphConfigurationException: GraphConfiguration could not be found or otherwise instantiated: [com.thinkaurelius.titan.tinkerpop.rexster.TitanGraphConfiguration]. Ensure that it is in Rexster's path.at com.tinkerpop.rexster.config.GraphConfigurationContainer.getGraphFromConfiguration(GraphConfigurationContainer.java:137)
at com.tinkerpop.rexster.config.GraphConfigurationContainer.<init>(GraphConfigurationContainer.java:54)
at com.tinkerpop.rexster.server.XmlRexsterApplication.reconfigure(XmlRexsterApplication.java:99)
at com.tinkerpop.rexster.server.XmlRexsterApplication.<init>(XmlRexsterApplication.java:47)
at com.tinkerpop.rexster.Application.<init>(Application.java:96)
at com.tinkerpop.rexster.Application.main(Application.java:188)
Caused by: java.lang.IllegalArgumentException: Could not instantiate implementation: com.thinkaurelius.titan.diskstorage.cassandra.astyanax.AstyanaxStoreManager
at com.thinkaurelius.titan.diskstorage.Backend.instantiate(Backend.java:355)
at com.thinkaurelius.titan.diskstorage.Backend.getImplementationClass(Backend.java:367)
at com.thinkaurelius.titan.diskstorage.Backend.getStorageManager(Backend.java:311)
at com.thinkaurelius.titan.diskstorage.Backend.<init>(Backend.java:121)
at com.thinkaurelius.titan.graphdb.configuration.GraphDatabaseConfiguration.getBackend(GraphDatabaseConfiguration.java:1173)
at com.thinkaurelius.titan.graphdb.database.StandardTitanGraph.<init>(StandardTitanGraph.java:75)
at com.thinkaurelius.titan.core.TitanFactory.open(TitanFactory.java:40)
at com.thinkaurelius.titan.tinkerpop.rexster.TitanGraphConfiguration.configureGraphInstance(TitanGraphConfiguration.java:25)
at com.tinkerpop.rexster.config.GraphConfigurationContainer.getGraphFromConfiguration(GraphConfigurationContainer.java:119)
Configuration file -
<rexster>
<http>
<server-port>7182</server-port>
<server-host>0.0.0.0</server-host>
<base-uri>http://localhost</base-uri>
<web-root>public</web-root>
<character-set>UTF-8</character-set>
<enable-jmx>false</enable-jmx>
<enable-doghouse>true</enable-doghouse>
<max-post-size>2097152</max-post-size>
<max-header-size>8192</max-header-size>
<upload-timeout-millis>30000</upload-timeout-millis>
<thread-pool>
<worker>
<core-size>8</core-size>
<max-size>8</max-size>
</worker>
<kernal>
<core-size>4</core-size>
<max-size>4</max-size>
</kernal>
</thread-pool>
<io-strategy>leader-follower</io-strategy>
</http>
<rexpro>
<server-port>7180</server-port>
<server-host>0.0.0.0</server-host>
<session-max-idle>1790000</session-max-idle>
<session-check-interval>3000000</session-check-interval>
<connection-max-idle>180000</connection-max-idle>
<connection-check-interval>3000000</connection-check-interval>
<enable-jmx>false</enable-jmx>
<thread-pool>
<worker>
<core-size>8</core-size>
<max-size>8</max-size>
</worker>
<kernal>
<core-size>4</core-size>
<max-size>4</max-size>
</kernal>
</thread-pool>
<io-strategy>leader-follower</io-strategy>
</rexpro>
<shutdown-port>7183</shutdown-port>
<shutdown-host>127.0.0.1</shutdown-host>
<graphs>
<graph>
<graph-name>graph</graph-name>
<graph-type>com.thinkaurelius.titan.tinkerpop.rexster.TitanGraphConfiguration</graph-type>
<graph-location>/tmp/titan</graph-location>
<graph-read-only>false</graph-read-only>
<properties>
<storage.hostname>ec2-52-22-199-210.amazonaws.com</storage.hostname>
<storage.backend>cassandra</storage.backend>
</properties>
<extensions>
<allows>
<allow>tp:gremlin</allow>
</allows>
</extensions>
</graph>
</graphs>
</rexster>