Error while following setting up local Flink Cluster #27

Hello I am new to flink and following the tutorials here to set up my local flink cluster on vmware environment. Everything goes fine before I tried to run the the application at step 4, which gives an error saying "Caused by: org.apache.flink.shaded.netty4.io.netty.channel.AbstractChannel$AnnotatedConnectException: Connection refused: localhost/127.0.0.1:8081".

Anyone knows what's wrong and how to solve the problem? Thanks very much!!