Vfrdtyky

Open your cmd.exe as administrator,

then Find the PID of port 4200

netstat -ano | findstr :4200

Here i have 3 PID :

• Red one is from "ng-serve" (127.0.0.1:4200) that LISTENING
  


• Green one is from "your browser"

kill only port 4200 (kill the red PID):

taskkill /PID 15940 /F

note : kill the green one will only lead your browser closed by force.

now you can do "ng-serve" to start your angular app at the same port 4200

Additional Stuff :

One liner : After looking a way to optimize this, Here is the One-liner command of this answer : (special thanks to : Josep Alsina for this tips)

for /f "tokens=5" %a in ('netstat -ano ^| find "4200" ^| find "LISTENING"') do taskkill /f /pid %a

On Mac OS X you need the following command:

sudo lsof -t -i tcp:4200 | xargs kill -9

Remember you need to kill Angular's web server with Command+C.

Not ctrl+Z,
you must run for stop ctrl+C
it's worked, I checking

Use this command to kill ng:

pkill -9 ng

ng serve --port <YOUR_GIVEN_PORT_NUMBER>

You should try above command to run on your given port.

I also faced the same error msg, so i tried ng serve --port 12012 and it worked fine.

When you use Ctrl+Z, you are going to suspend a running task but not to kill it. You can later use command fg to resume the task.
If you want to quit ng serve, you should use Ctrl+C instead, in which will also release the 4200 port.

We can forcefully kill the port by following command.

kill -2 $(lsof -t -i:4200)

ng serve --port 4201 --live-reload-port 4200

and access using localhost:4201

This should work as a temporary solution.

or

try listing port usage using
lsof -i:4200

and kill it manually using
sudo kill -9 <Process PID using port 4200>

For Windows:

Open Command Prompt and

type: netstat -a -o -n

Find the PID of the process that you want to kill.

Type: taskkill /F /PID 16876

This one 16876 - is the PID for the process that I want to kill - in that case, the process is 4200 - check the attached file.you can give any port number.

Now, Type : ng serve to start your angular app at the same port 4200

netstat -anp | grep ":4200"

This will tell you who's got the port.

The most simple one line command:

 sudo fuser -k 4200/tcp

You can also try with this to run your application in visual studio code -:

ng serve --open --port 4201

you can give any port number.

you can use fuser -k 4200/tcp if it is Linux Operating system

Kill process and close the terminal which you used for running the app on that port.

Instead of killing the whole process or using ctrl+z, you can simply use ctrl+c to stop the server and can happily use ng serve command without any errors or if you want to run on a different port simply use this command ng serve --port portno(ex: ng serve --port 4201).

With ctrl + z you put the program in the background.
On Linux you can get the session back in the foreground with the following command:

fg ng serve

You don't need to kill the process.

If you compiling your angular JS code in both CMD and IDE then this issue occur. In CMD, your angular JS code compile automatically whenever you change your angular JS code in IDE and then your IDE want to occupy the same port i.e 4200 which is occupied by CMD already
So, there is a simple solution for this issue, just close your cmd while compiling your code in IDE.

I was facing the same issue every time I have to kill the port.

I tried ./node_modules/.bin/ng serve --proxy-config proxy.conf.json --host 0.0.0.0 Instead of npm start and its works

On linux mint 17, this is working.

kill -9 $(lsof -t -i:4200)

It is possible to change port in .angular-cli file. For example:

"defaults": {

    "styleExt": "css",

    "component": {},

    "serve": {

      "port": 4205

    }

  }

In addition, it is necessary to add this to your package.json:

"ng": "ng",

"start": "ng serve"

It says already we are running the services with port no 4200 please use another port instead of 4200. Below command is to solve the problem

ng serve --port 4300

Port 4200 is already in use. Use '--port' to specify a different port

This means that you already have another service running on port 4200. If this is the case
you can either . shut down the other service. use the --port flag when running ng
serve like this:

 ng serve --port 9001

Another thing to notice is that, on some machines, the domain localhost may not work.
You may see a set of numbers such as 127.0.0.1. When you run ng serve it should show
you what URL the server is running on, so be sure to read the messages on your machine
to find your exact development URL.

netstat -plnet

tcp 0 0 127.0.0.1:4200 0.0.0.0:* LISTEN 1001 63955 7077/ng

kill -9 7077

again start your ng serve.

In Windows; In command prompt which is running your ng serve just click and press keys:

ctrl + c

It will ask you: Terminate batch job (Y/N)?
and you type Y

As first step after any changes, I use ng build, then ng serve. It works without any problems.

Just restart the IDE you are using, then it will work.

Only thing that works for me is to restart my system / device...

Using Webstorm IDE by JetBrains.

To Access project outside localhost

Example:

ng serve --host 192.168.2.2:7006