Failed to listen on 127.0.0.1:8000 (reason: Address already in use) code example

Example 1: Address already in use - bind(2) for "127.0.0.1" port 3000 (Errno::EADDRINUSE)

lsof -wni tcp:3000 
kill -9 PID_number

Example 2: [Thu Nov 5 15:20:23 2020] Failed to listen on localhost:3200 (reason: Address already in use)

ps -ef | grep php
kill -9 14315