How to fix "HTTP could not register URL http://... because TCP port xxx is being used by another application"?

Question

From: https://stackoverflow.com/q/73283828/1188758

I'm getting the exception:

HTTP could not register URL http://+:50005/JTCrawlerAppServer/ because TCP port 50005 is being used by another application.: The process cannot access the file because it is being used by another process

This is running in a WPF app. It ran fine last week, and runs fine on another computer, so I don't know what changed. I've rebooted, run it as administrator, tried a different port number, and several other suggestions from StackOverflow, but no change. Running "netstat -o -n -a" shows no one else on that port. Running "netsh http show url" shows that I should have permission:

Reserved URL : http://+:50005/
User: \Everyone
Listen: Yes
Delegate: No
SDDL: D:(A;;GX;;;WD)

Here's the relevant app.cfg and C# code:

<system.serviceModel>
<behaviors>
<serviceBehaviors>
<behavior name="">
<serviceMetadata httpGetEnabled="true" httpsGetEnabled="true" />
<serviceDebug includeExceptionDetailInFaults="false" />
</behavior>
</serviceBehaviors>
</behaviors>
<services>
<service name="JTCrawlerApp.JTCrawlerAppService">
<endpoint address="" binding="basicHttpBinding" contract="JTCrawlerApp.IJTCrawlerAppService">
<identity>
<dns value="localhost" />
</identity>
</endpoint>
<endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
<host>
<baseAddresses>
<!-- Don't let this through the firewall!! -->
<add baseAddress="http://localhost:50005/JTCrawlerAppServer" />
</baseAddresses>
</host>
</service>
</services>
</system.serviceModel>

public class RunWebServiceCommand : BaseCrawlerCommand
{
// Implementatiion data.
public static string ServerEndpoint = "JTCrawlerAppServer";
protected ServiceHost Host;
// ...
protected bool OnInitializeWebService()
{
try
{
Host = new ServiceHost(typeof(JTCrawlerAppService));

        // Service host is opened on the UI thread  
        Host.AddServiceEndpoint(  
            typeof(IJTCrawlerAppService),  
            new WSHttpBinding(),  
            ServerEndpoint);  

        Host.Open();  

        PutLogMessage("RunWebServiceCommand: Service started.");  

        return true;  
    }  
    catch (Exception exc)  
    {  
        PutExceptionErrorLogMessage("Error starting JTCrawlerApp web service", exc);  
    }  

    return false;  
}  

}
Here is the stack trace from the exception:

at System.ServiceModel.Channels.SharedHttpTransportManager.OnOpen()
at System.ServiceModel.Channels.TransportManager.Open(TransportChannelListener channelListener)
at System.ServiceModel.Channels.TransportManagerContainer.Open(SelectTransportManagersCallback selectTransportManagerCallback)
at System.ServiceModel.Channels.TransportChannelListener.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.HttpChannelListener`1.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.Dispatcher.ChannelDispatcher.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.ServiceHostBase.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open()
at JTCrawlerApp.Commands.RunWebServiceCommand.OnInitializeWebService() in C:\JTLanguage\JTCrawlerApp\Commands\RunWebServiceCommand.cs:line

It's curious the duplicate CommunicationObject.Open calls. Is it because it's switching to another thread?

Answer 1

Hi @John Thompson ,

If you still want to use port 50005, try the following steps:

1. Used in the CMD command netstat aon | findstr searches "50005", will get a PID.
2. Find the process corresponding to the PID in the task manager and terminate it.
3. Try again to see if port 50005 can be used.

If there are other important programs on this port, you can try testing on another port.

Best Regards,
Jiayao Wu

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