Information of the environment: ======================== Zabbix: 3.4.8 (installed via RPM) Linux: CentOS Linux release 7.4.1708 (Core) 64 bit, with SELinux disabled Zabbix and Java RPMs Installed: [ root@zabbix ~]# [ root@zabbix ~]# rpm -qa | grep zabbix zabbix-agent-3.4.8-1.el7.x86_64 zabbix-web-mysql-3.4.8-1.el7.noarch zabbix-release-3.4-2.el7.noarch zabbix-web-3.4.8-1.el7.noarch zabbix-server-mysql-3.4.8-1.el7.x86_64 zabbix-get-3.4.8-1.el7.x86_64 zabbix-java-gateway-3.4.8-1.el7.x86_64 [ root@zabbix ~]# [ root@zabbix ~]# rpm -qa | grep java tzdata-java-2018e-3.el7.noarch java-1.8.0-openjdk-accessibility-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-src-debug-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-demo-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-devel-1.8.0.171-7.b10.el7.x86_64 java-atk-wrapper-0.30.4-5.el7.x86_64 java-1.8.0-openjdk-demo-debug-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-javadoc-zip-1.8.0.171-7.b10.el7.noarch java-1.8.0-openjdk-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-debug-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-devel-debug-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-javadoc-zip-debug-1.8.0.171-7.b10.el7.noarch java-1.8.0-openjdk-src-1.8.0.171-7.b10.el7.x86_64 python-javapackages-3.4.1-11.el7.noarch java-1.8.0-openjdk-headless-1.8.0.171-7.b10.el7.x86_64 zabbix-java-gateway-3.4.8-1.el7.x86_64 java-1.8.0-openjdk-headless-debug-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-accessibility-debug-1.8.0.171-7.b10.el7.x86_64 java-1.8.0-openjdk-javadoc-debug-1.8.0.171-7.b10.el7.noarch java-1.8.0-openjdk-javadoc-1.8.0.171-7.b10.el7.noarch javapackages-tools-3.4.1-11.el7.noarch [ root@zabbix ~]# Problem: ========= After completing the installation and configuration of the Zabbix Java Gateway (without having any JMX monitoring configured within Zabbix), the following error message appears. 2018-05-18 14:24:26.057 [main] INFO com.zabbix.gateway.JavaGateway - Zabbix Java Gateway 3.4.8 (revision 79252) has started 2018-05-18 14:24:26.077 [main] INFO com.zabbix.gateway.JavaGateway - listening on 0.0.0.0/0.0.0.0:10052 2018-05-18 14:25:09.939 [pool-1-thread-1] WARN com.zabbix.gateway.SocketProcessor - error processing request com.zabbix.gateway.ZabbixException: java.io.IOException: Failed to retrieve RMIServer stub: javax.naming.CommunicationException [Root exception is java.rmi.ConnectIOException: non-JRMP server at remote endpoint]         at com.zabbix.gateway.JMXItemChecker.getValues(JMXItemChecker.java:98) ~[zabbix-java-gateway-3.4.8.jar:na]         at com.zabbix.gateway.SocketProcessor.run(SocketProcessor.java:63) ~[zabbix-java-gateway-3.4.8.jar:na]         at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_171]         at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_171]         at java.lang.Thread.run(Thread.java:748) [na:1.8.0_171] Caused by: java.io.IOException: Failed to retrieve RMIServer stub: javax.naming.CommunicationException [Root exception is java.rmi.ConnectIOException: non-JRMP server at remote endpoint]         at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:369) ~[na:1.8.0_171]         at javax.management.remote.JMXConnectorFactory.connect(JMXConnectorFactory.java:270) ~[na:1.8.0_171]         at com.zabbix.gateway.ZabbixJMXConnectorFactory$1.run(ZabbixJMXConnectorFactory.java:76) ~[zabbix-java-gateway-3.4.8.jar:na]         at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_171]         at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[na:1.8.0_171]         ... 3 common frames omitted Caused by: javax.naming.CommunicationException: null         at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:136) ~[na:1.8.0_171]         at com.sun.jndi.toolkit.url.GenericURLContext.lookup(GenericURLContext.java:205) ~[na:1.8.0_171]         at javax.naming.InitialContext.lookup(InitialContext.java:417) ~[na:1.8.0_171]         at javax.management.remote.rmi.RMIConnector.findRMIServerJNDI(RMIConnector.java:1955) ~[na:1.8.0_171]         at javax.management.remote.rmi.RMIConnector.findRMIServer(RMIConnector.java:1922) ~[na:1.8.0_171]         at javax.management.remote.rmi.RMIConnector.connect(RMIConnector.java:287) ~[na:1.8.0_171]         ... 7 common frames omitted Caused by: java.rmi.ConnectIOException: non-JRMP server at remote endpoint         at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:248) ~[na:1.8.0_171]         at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202) ~[na:1.8.0_171]         at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:338) ~[na:1.8.0_171]         at sun.rmi.registry.RegistryImpl_Stub.lookup(RegistryImpl_Stub.java:112) ~[na:1.8.0_171]         at com.sun.jndi.rmi.registry.RegistryContext.lookup(RegistryContext.java:132) ~[na:1.8.0_171]         ... 12 common frames omitted 2018-05-18 14:26:09.995 [pool-1-thread-2] WARN com.zabbix.gateway.SocketProcessor - error processing request com.zabbix.gateway.ZabbixException: java.io.IOException: Failed to retrieve RMIServer stub: javax.naming.CommunicationException [Root exception is java.rmi.ConnectIOException: non-JRMP server at remote endpoint]         at com.zabbix.gateway.JMXItemChecker.getValues(JMXItemChecker.java:98) ~[zabbix-java-gateway-3.4.8.jar:na]         at com.zabbix.gateway.SocketProcessor.run(SocketProcessor.java:63) ~[zabbix-java-gateway-3.4.8.jar:na] ... ... ... The Zabbix Java Gateway log file is attached zipped. ->File "zabbix_java_gateway.log.zip" attached. The following configuration files are attached: "zabbix_server.conf" "zabbix_java_gateway.conf" "zabbix_java_gateway_logback.xml" On the Host Configuration screen, JMX availability is red according to the attached screen -> File "jmx_red.png"attached. Can you please help me identify and solve the problem? I have already accessed and read this "note" https://support.zabbix.com/browse/ZBXNEXT-1274 but I found nothing in it to help. Thank you very much in advance! Adriano