title: An unhandled exception occurred: Port 4200 is already in use. Use '--port' to specify a different port
body: <p><a href="https://i.stack.imgur.com/xoPF4.png" rel="nofollow noreferrer">I tried to access localhost:4200 on my browser for my project. And the compile error message showed up each time I opened localhost4200. It says port 4200 is already in use. I tried online method like Ctrl+C but it doesn't work and have the error message shows up again. Could you help me with this problem? Thanks! The first screenshot is what my browser web page looks like when I go to localhost 4200.</a></p>
  <p><a href="https://i.stack.imgur.com/wWfyw.png" rel="nofollow noreferrer">This is what showed me in the terminal window after I run npm start. I could not run ng serve for some reasons. But the npm start works fine for me before.</a></p>