Unable to start Kestrel. System.IO.IOException: Failed to bind to address http://localhost:5000 on the IPv4 loopback interface: port already in use.

Steps to reproduce

1 - open VSCode 2 - Load the project with Code . 2 - run the project using Dotnet watch run

Expected behavior

to make the app available http://localhost:5000

Actual behavior

Unable to start Kestrel. System.IO.IOException: Failed to bind to address http://localhost:5000 on the IPv4 loopback interface: port already in use.

Environment data

dotnet --info output:

Unable to start Kestrel.
System.IO.IOException: Failed to bind to address http://localhost:5000 on the IPv4 loopback interface: port already in use. ---> System.AggregateException: One or more errors occurred. (Error -48 EADDRINUSE address already in use) ---> Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.UvException: Error -48 EADDRINUSE address already in use
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.Libuv.ThrowError(Int32 statusCode)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.Libuv.tcp_getsockname(UvTcpHandle handle, SockAddr& addr, Int32& namelen)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.UvTcpHandle.GetSockIPEndPoint()
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.TcpListenerPrimary.CreateListenSocket()
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Listener.<StartAsync>b__8_0(Object state)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.ListenerPrimary.<StartAsync>d__12.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.KestrelEngine.CreateServer(ServerAddress address)
   at Microsoft.AspNetCore.Server.Kestrel.KestrelServer.Start[TContext](IHttpApplication`1 application)
   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.Server.Kestrel.KestrelServer.Start[TContext](IHttpApplication`1 application)

Unhandled Exception: System.IO.IOException: Failed to bind to address http://localhost:5000 on the IPv4 loopback interface: port already in use. ---> System.AggregateException: One or more errors occurred. (Error -48 EADDRINUSEaddress already in use) ---> Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.UvException: Error -48 EADDRINUSE address already in use
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.Libuv.ThrowError(Int32 statusCode)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.Libuv.tcp_getsockname(UvTcpHandle handle, SockAddr& addr, Int32& namelen)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.UvTcpHandle.GetSockIPEndPoint()
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.TcpListenerPrimary.CreateListenSocket()
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.Listener.<StartAsync>b__8_0(Object state)
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.ListenerPrimary.<StartAsync>d__12.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.Kestrel.Internal.KestrelEngine.CreateServer(ServerAddress address)
   at Microsoft.AspNetCore.Server.Kestrel.KestrelServer.Start[TContext](IHttpApplication`1 application)
   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.Server.Kestrel.KestrelServer.Start[TContext](IHttpApplication`1 application)
   at Microsoft.AspNetCore.Hosting.Internal.WebHost.Start()
   at Microsoft.AspNetCore.Hosting.WebHostExtensions.Run(IWebHost host, CancellationToken token, String shutdownMessage)
   at Microsoft.AspNetCore.Hosting.WebHostExtensions.Run(IWebHost host)
   at Welocate.Program.Main(String[] args) in /Users/admin/welocate/Program.cs:line 20
watch : Exited with error code 134
watch : Waiting for a file to change before restarting dotnet...

[asmaa3107]

ok, thanks.

For others having the same issue, here is the steps:

on terminal on MAC:

1 - soft -t -I :portNumber
process ID will be display (in case the port is in use ) ex: 10872
2 - kill -9 10872 (to kill the process)

I still have the same issue Win 10??

[enginmarshall]

On Windows: I was getting this error in a .dotnet core react template application and this little change of port number helped: In launchSettings.json from: “applicationUrl”: “https://localhost:5001;http://localhost:5000”, to: “applicationUrl”: “https://localhost:7580;http://localhost:5000”,