Port Wars: Hunt Down and Terminate Rogue Processes!

On macOS use the command lsof -i with the port number to find out what is running on a specific port.

sudo lsof -i :<PortNumber>

This will work for linux as well ;)

Kill the process running on a specific port

use the kill command with the -9 option and the port PID number to kill a process

kill -9 <PID>