"Failed to spawn Radzen.Server process" error

Radzen Studio Blazor Server
1

I am downloaded the latest version of radzen and when I create a new application, I get the following error. What could the underlying issue be?

[2021-03-31 23:29:41.678] [error] Failed to spawn Radzen.Server process. Unhandled exception. System.IO.IOException: Failed to bind to address http://localhost:4000.
 ---> System.AggregateException: One or more errors occurred. (An attempt was made to access a socket in a way forbidden by its access permissions.) (An attempt was made to access a socket in a way forbidden by its access permissions.)
 ---> System.Net.Sockets.SocketException (10013): An attempt was made to access a socket in a way forbidden by its access permissions.
   at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, String callerName)
   at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.Sockets.Socket.Bind(EndPoint localEP)
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketConnectionListener.<Bind>g__BindSocket|13_0(<>c__DisplayClass13_0& )
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketConnectionListener.Bind()
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketTransportFactory.BindAsync(EndPoint endpoint, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure.TransportManager.BindAsync(EndPoint endPoint, ConnectionDelegate connectionDelegate, EndpointConfig endpointConfig)
   at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerImpl.<>c__DisplayClass29_0`1.<<StartAsync>g__OnBind|0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.BindEndpointAsync(ListenOptions endpoint, AddressBindContext context)
   at Microsoft.AspNetCore.Server.Kestrel.Core.LocalhostListenOptions.BindAsync(AddressBindContext context)
   --- End of inner exception stack trace ---
 ---> (Inner Exception #1) System.Net.Sockets.SocketException (10013): An attempt was made to access a socket in a way forbidden by its access permissions.
   at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, String callerName)
   at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
   at System.Net.Sockets.Socket.Bind(EndPoint localEP)
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketConnectionListener.<Bind>g__BindSocket|13_0(<>c__DisplayClass13_0& )
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketConnectionListener.Bind()
   at Microsoft.AspNetCore.Server.Kestrel.Transport.Sockets.SocketTransportFactory.BindAsync(EndPoint endpoint, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Infrastructure.TransportManager.BindAsync(EndPoint endPoint, ConnectionDelegate connectionDelegate, EndpointConfig endpointConfig)
   at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerImpl.<>c__DisplayClass29_0`1.<<StartAsync>g__OnBind|0>d.MoveNext()
--- End of stack trace from previous location ---
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.BindEndpointAsync(ListenOptions endpoint, AddressBindContext context)
   at Microsoft.AspNetCore.Server.Kestrel.Core.LocalhostListenOptions.BindAsync(AddressBindContext context)<---

   --- End of inner exception stack trace ---
   at Microsoft.AspNetCore.Server.Kestrel.Core.LocalhostListenOptions.BindAsync(AddressBindContext context)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.AddressesStrategy.BindAsync(AddressBindContext context)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.AddressBinder.BindAsync(IEnumerable`1 listenOptions, AddressBindContext context)
   at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerImpl.BindAsync(CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Server.Kestrel.Core.KestrelServerImpl.StartAsync[TContext](IHttpApplication`1 application, CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Hosting.WebHost.StartAsync(CancellationToken cancellationToken)
   at Microsoft.AspNetCore.Hosting.WebHost.Start()
   at Radzen.Server.Program.<>c__DisplayClass0_0.<Main>b__0()
   at McMaster.Extensions.CommandLineUtils.CommandLineApplicationExtensions.<>c__DisplayClass9_0.<OnExecute>b__0()
   at McMaster.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
   at Radzen.Server.Program.Main(String[] args)
2

I searched online for this error and found this blog post. It seems port 4000 is forbidden for some reason.

1 Like
3

Okay. How do we change the port being used by Radzen?

4

I just updated today and am now getting this message too when I create a new project in the Radzen app. My application is set to run on 5000, not 4000. why would I get this message for a different port? What's the fix for this?

Thanks

5

Hi @cottomatte,

The Radzen.Server process is used to preview your application in Radzen. It isn't related to the port your application runs on. This error usually means that port 4000 is free but for some reason Radzen does not have permission to listen to it. Usually restarting your machine would solve the problem.

6

Thank you for the quick response. I'll give that a try. Thanks again