NodeManager killing itself after a short period of time

I have a new 12.1,3 setup 1Admin Server with 1 machine with 1 managed server 2 Managed Servers on two external machines The nodemanager on the Adminserver machine keeps dying with the following error... somtimes within 10 minutes of startup. I have tried removing the server, changing the server port number. Not sure what else to try Error is as follows /u01/app/oracle/Middleware/wlserver/server/bin/startNodeManager.sh: line 128: 18182 Killed            "${JAVA_HOME}/bin/java" ${JAVA_PROPERTIES} ${JAVA_VM} ${MEM_ARGS} ${JAVA_OPTIONS} -Djava.security.policy="${WL_HOME}/server/lib/weblogic.policy" -Dweblogic.nodemanager.JavaHome="${JAVA_HOME}" weblogic.NodeManager -v Any help would be appreciated