Error -98 EADDRINUSE Address Already Used on Ubuntu

Question

I just created a simple .NET webapi project using https://github.com/omnisharp/generator-aspnet

Then try to run the application in the Ubuntu subsystem.

When I start dotnet start , I get an error:

 Unhandled Exception: System.AggregateException: One or more errors occurred. (Error -98 EADDRINUSE address already in use) ---> Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.UvException: Error -98 EADDRINUSE address already in use at Microsoft.AspNetCore.Server.Kestrel.Internal.Networking.Libuv.Check(Int32 statusCode) 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.<>c.<StartAsync>b__6_0(Object state) --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at Microsoft.AspNetCore.Server.Kestrel.Internal.Http.ListenerPrimary.<StartAsync>d__11.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](IHttpApplication1 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 WebApp.Program.Main(String[] args) 

However, when I run the application only on windows using the same command in cmd , everything works fine.

Any thoughts on how to fix this? WebApi using port 5000 by default.

UPDATE:

I just specify the default built-in port using .UseUrls("http://*:5000")

 var host = new WebHostBuilder() .UseConfiguration(config) .UseKestrel() .UseContentRoot(Directory.GetCurrentDirectory()) .UseIISIntegration() .UseStartup<Startup>() .UseUrls("http://*:5000") .Build(); 

So now it is working fine. However, I do not change the value of the port. Any thoughts why port 5000 does not work on Ubuntu when it was not listed?