windows-hyperv

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.