ng server - listen EACCES: permission denied 127.0.0.1:4200

Question

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?

Answer 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.

Answer 2

It sounds like your port is taken already.

You should kill the use in port 4200.

Answer 3

1. check might port already allocated for another application.

netstat -ano | findstr "4200"

2. If you are using Docker might docker allocated this port (stop docker)

3. Final solution restarting PC

Answer 4

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.