Elasticsearch 2.2.0 - ClusterBlockException while accessing through rest

Hi,

I have started elasticsearch as a standalone process.After it's starting i have tried to run the "curl 10.2..1.50:9202/_cat/shards" .But it's returning the following "ClusterBlockException".Also in log it seems a rest suppressed .Can anyone tell me i have missed anything or what is the root cause for this exception.

[2016-02-18 08:45:28,212][INFO ][transport ] [10.2.1.50] publish_address {10.2.1.50:9302}, bound_addresses {10.2.1.50:9302}
[2016-02-18 08:45:28,239][INFO ][discovery ] [10.2.1.50] elasticsearch-2.1.0/_m-haJxSRZeOlqn22JL-jw
[2016-02-18 08:45:31,274][INFO ][cluster.service ] [10.2.1.50] new_master {10.2.1.50}{_m-haJxSRZeOlqn22JL-jw}{10.2.1.50}{10.2.1.50:9302}{max_local_storage_nodes=1}, reason: zen-disco-join(elected_as_master, [0] joins received)
[2016-02-18 08:45:31,312][INFO ][http ] [10.2.1.50] publish_address {10.2.1.50:9202}, bound_addresses {10.2.1.50:9202}
[2016-02-18 08:45:31,312][INFO ][node ] [10.2.1.50] started
[2016-02-18 08:45:45,280][INFO ][rest.suppressed ] /_cat/shards Params: {}
ClusterBlockException[blocked by: [SERVICE_UNAVAILABLE/1/state not recovered / initialized];]
at org.elasticsearch.cluster.block.ClusterBlocks.globalBlockedException(ClusterBlocks.java:154)
at org.elasticsearch.action.admin.indices.stats.TransportIndicesStatsAction.checkGlobalBlock(TransportIndicesStatsAction.java:70)
at org.elasticsearch.action.admin.indices.stats.TransportIndicesStatsAction.checkGlobalBlock(TransportIndicesStatsAction.java:47)
at org.elasticsearch.action.support.broadcast.node.TransportBroadcastByNodeAction$AsyncAction.(TransportBroadcastByNodeAction.java:237)
at org.elasticsearch.action.support.broadcast.node.TransportBroadcastByNodeAction.doExecute(TransportBroadcastByNodeAction.java:217)
at org.elasticsearch.action.support.broadcast.node.TransportBroadcastByNodeAction.doExecute(TransportBroadcastByNodeAction.java:77)

Thanks
Moni