压力机 9 台，控制机 1 台，其中同步定时器设置的 700 并发，相当于 700*9 的总并发数，但是远程启动所有压力机完成后，样本数却少于并发数，求教是哪些问题引起的。

021-09-24 14:57:01,843 ERROR o.a.j.t.JMeterThread: Test failed!
org.apache.jorphan.util.JMeterError: Could not return sample
    at org.apache.jmeter.samplers.StandardSampleSender.sampleOccurred(StandardSampleSender.java:69) ~[ApacheJMeter_core.jar:5.4.1]
    at org.apache.jmeter.samplers.RemoteListenerWrapper.sampleOccurred(RemoteListenerWrapper.java:94) ~[ApacheJMeter_core.jar:5.4.1]
    at org.apache.jmeter.threads.ListenerNotifier.notifyListeners(ListenerNotifier.java:58) ~[ApacheJMeter_core.jar:5.4.1]
    at org.apache.jmeter.threads.JMeterThread.notifyListeners(JMeterThread.java:1024) ~[ApacheJMeter_core.jar:5.4.1]
    at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:579) ~[ApacheJMeter_core.jar:5.4.1]
    at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:489) ~[ApacheJMeter_core.jar:5.4.1]
    at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:256) [ApacheJMeter_core.jar:5.4.1]
    at java.lang.Thread.run(Unknown Source) [?:1.8.0_202]
Caused by: java.rmi.ConnectException: Connection refused to host: 115.227.33.18; nested exception is: 
    java.net.ConnectException: Connection timed out: connect
    at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.server.UnicastRef.invoke(Unknown Source) ~[?:1.8.0_202]
    at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source) ~[?:1.8.0_202]
    at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source) ~[?:1.8.0_202]
    at com.sun.proxy.$Proxy20.sampleOccurred(Unknown Source) ~[?:?]
    at org.apache.jmeter.samplers.StandardSampleSender.sampleOccurred(StandardSampleSender.java:66) ~[ApacheJMeter_core.jar:5.4.1]
    ... 7 more
Caused by: java.net.ConnectException: Connection timed out: connect
    at java.net.DualStackPlainSocketImpl.connect0(Native Method) ~[?:1.8.0_202]
    at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source) ~[?:1.8.0_202]
    at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source) ~[?:1.8.0_202]
    at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source) ~[?:1.8.0_202]
    at java.net.AbstractPlainSocketImpl.connect(Unknown Source) ~[?:1.8.0_202]
    at java.net.PlainSocketImpl.connect(Unknown Source) ~[?:1.8.0_202]
    at java.net.SocksSocketImpl.connect(Unknown Source) ~[?:1.8.0_202]
    at java.net.Socket.connect(Unknown Source) ~[?:1.8.0_202]
    at java.net.Socket.connect(Unknown Source) ~[?:1.8.0_202]
    at java.net.Socket.<init>(Unknown Source) ~[?:1.8.0_202]
    at java.net.Socket.<init>(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source) ~[?:1.8.0_202]
    at sun.rmi.server.UnicastRef.invoke(Unknown Source) ~[?:1.8.0_202]
    at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(Unknown Source) ~[?:1.8.0_202]
    at java.rmi.server.RemoteObjectInvocationHandler.invoke(Unknown Source) ~[?:1.8.0_202]
    at com.sun.proxy.$Proxy20.sampleOccurred(Unknown Source) ~[?:?]
    at org.apache.jmeter.samplers.StandardSampleSender.sampleOccurred(StandardSampleSender.java:66) ~[ApacheJMeter_core.jar:5.4.1]
    ... 7 more