Error: listen EADDRINUSE: address already in use :::4001 code example

Example 1: Error: listen EADDRINUSE: address already in use :::9000

step-1 Enter commond to see running ports & processes
ps -ef
step-2 To stop port and processes
sudo kill {PID}

Example 2: Error: listen EADDRINUSE: address already in use :::31641

ps aux | grep node //gets all the nodes and list of PID
kill -9 {PID}