You can search on how to kill that process.
For Linux/Mac OS search (sudo) run this in the terminal:
$ lsof -i tcp:8080 $ kill -9 PID
On Windows:
netstat -ano | findstr :8080 tskill typeyourLISTENINGPIDhere

You can search on how to kill that process.
For **Linux/Mac** OS search `(sudo) run` this in the terminal:
$ lsof -i tcp:3000 $ kill -9 PID
**On Windows:**
netstat -ano | findstr :3000 tskill typeyourPIDhere
*change `tskill` for `taskkill` in git bash*