'ng server - listen EACCES: permission denied 127.0.0.1:4200

I have no problem in do ng serve using 127.0.0.1:4200.

But today, when I do ng serve An unhandled exception occurred: listen EACCES: permission denied 127.0.0.1:4200

Is there a way to solve this problem permanently?

angular

Solution 1:^[1]

I have solved this issue by simply going to Control Panel\Network and Internet\Network Connections and then I disabled all the Hyper-V Connections/Adapters and I kept the ones I use like the Wifi and Physical Ethernet Adapter.

No restart needed. Once done, try to run your Angular app on 4200 and it should work.

UPDATE

Alternative Solutions:

Sometimes just restarting Windows NAT driver can fix the issue:

open CMD/PowerShell and type net stop winnat and then net start winnat.

If that did not help then, try to stop the Windows NAT Driver and update the excludedportrange as follows :

type netsh int ipv4 add excludedportrange protocol=tcp startport=4200 numberofports=1 if you want to exclude port 4200 only if you want more just update numberofports
then start the Windows NAT Driver again and run your App.

Solution 2:^[2]

check might port already allocated for another application.

netstat -ano | findstr "4200"

If you are using Docker might docker allocated this port (stop docker)
Final solution restarting PC

Solution 3:^[3]

For me happens after Windows 10 Update to build 2009.

There is a network adapter which is blocking your port.

For @p90n33r was Hyper-V.

For me was Wifi adapter before I use ethernet port.

Try disable any adapters to test it.

No restart needed.

Solution 4:^[4]

This happens to me while trying to run 2 Angular apps at the same time. So they both targetted 4200 port. I can recommend two solutions.

Restart the PC. Very simple.
Use a different port for ng serve -o

You can modify the package.json file's start section as ng serve -o --port 4401 to make it permanent. (Any port number will do the trick) and on the terminal just execute the command to run the app as npm start

Solution 5:^[5]

I had the same error, also after rebooting several times. No application using the port. Finally a brainwave to turn off "Azure VPN", which we use locally to connect to our Cloud Network.

So if someone else bumbs into this error: Turn off "Azure VPN" and see if that is the issue. I don't know how to fix it keeping it on.

Solution 6:^[6]

For me is the Microsoft Wi-Fi Direct Virtual which enables by "Screen mirroring and projecting to your PC" Settings.

Just set "Always available" to "Always close" fix it.

Solution 7:^[7]

If you are on a Mac machine and see this type of error, then try running your command with an elevated access.
This can be done by prepending sudo before your command.

For eg: sudo npm start or sudo ng serve, etc.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1
Solution 2	harshavardhan athaluri
Solution 3	Andre Mesquita
Solution 4	SurenSaluka
Solution 5	rfcdejong
Solution 6	imckl
Solution 7

'ng server - listen EACCES: permission denied 127.0.0.1:4200

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