Standalone JMX client fails to connect with Operation failed with status WAITING

Issue

When I run a standalone JMX client like this solution for MBean metrics collection, I sometimes get the following message on the client-side. What are possible causes?

Exception in thread "main" java.lang.RuntimeException: Operation failed with status WAITING
    at org.jboss.remotingjmx.RemotingConnector.internalRemotingConnect(RemotingConnector.java:238)
    at org.jboss.remotingjmx.RemotingConnector.internalConnect(RemotingConnector.java:151)
    at org.jboss.remotingjmx.RemotingConnector.connect(RemotingConnector.java:102)
    at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:268)
    at JMXExample.main(JMXExample.java:13)