Es 2.1.0 keep throwing exception

[DEBUG][action.admin.cluster.node.info] [node1] failed to execute on node [yQYHZ3hxTWOwrQPq8w4rrQ]
RemoteTransportException[[node2][node2:9305][cluster:monitor/nodes/info[n]]]; nested: NotSerializableExceptionWrapper;
Caused by: NotSerializableExceptionWrapper[null]
at java.util.ArrayList.sort(ArrayList.java:1456)
at java.util.Collections.sort(Collections.java:175)
at org.elasticsearch.action.admin.cluster.node.info.PluginsInfo.getInfos(PluginsInfo.java:55)
at org.elasticsearch.action.admin.cluster.node.info.PluginsInfo.writeTo(PluginsInfo.java:86)
at org.elasticsearch.action.admin.cluster.node.info.NodeInfo.writeTo(NodeInfo.java:284)
at org.elasticsearch.transport.netty.NettyTransportChannel.sendResponse(NettyTransportChannel.java:97)
at org.elasticsearch.transport.netty.NettyTransportChannel.sendResponse(NettyTransportChannel.java:75)
at org.elasticsearch.action.support.nodes.TransportNodesAction$NodeTransportHandler.messageReceived(TransportNodesAction.java:211)
at org.elasticsearch.action.support.nodes.TransportNodesAction$NodeTransportHandler.messageReceived(TransportNodesAction.java:207)
at org.elasticsearch.transport.netty.MessageChannelHandler$RequestHandler.doRun(MessageChannelHandler.java:299)
at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

Are you running the same version on all your nodes and clients?

sure. same 2.1.0

Check your plugins, it seems you have a plugin with null or something strange as name.