主分片未激活或未分配是已知节点？

我在Windows 8上运行弹性搜索版本4.1.我试图通过java索引文档.运行JUNIT测试时,错误如下所示.

org.elasticsearch.action.UnavailableShardsException: [wms][3] Primary shard is not active or isn't assigned is a known node. Timeout: [1m], request: index {[wms][video][AUpdb-bMQ3rfSDgdctGY], source[{
    "fleetNumber": "45",
    "timestamp": "1245657888",
    "geoTag": "73.0012312,-123.00909",
    "videoName": "timestamp.mjpeg",
    "content": "ASD123124NMMM"
}]}
    at org.elasticsearch.action.support.replication.TransportShardReplicationOperationAction$AsyncShardOperationAction.retryBecauseUnavailable(TransportShardReplicationOperationAction.java:784)
    at org.elasticsearch.action.support.replication.TransportShardReplicationOperationAction$AsyncShardOperationAction.doStart(TransportShardReplicationOperationAction.java:402)
    at org.elasticsearch.action.support.replication.TransportShardReplicationOperationAction$AsyncShardOperationAction$3.onTimeout(TransportShardReplicationOperationAction.java:500)
    at org.elasticsearch.cluster.ClusterStateObserver$ObserverClusterStateListener.onTimeout(ClusterStateObserver.java:239)
    at org.elasticsearch.cluster.service.InternalClusterService$NotifyTimeout.run(InternalClusterService.java:497)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)

我无法弄清楚,为什么会导致此错误发生.当删除数据或索引工作正常.可能的原因可能是什么.