Today, we are going to discuss a common issue that you may find when running WCF RIA service on a shared hosting server., as the premier ASP.NET and Windows Hosting provider, proudly presents this article to anyone and we believe it will help many ASP.NET communities; especially to those who are using WCF RIA Service. In case you are looking for WCF RIA Service Hosting, you can always consider and you can start from our lowest Standard Plan @$4.99/month to host your WCF-service site.

One of the most common errors that you may find when running your WCF RIA Service on a shared hosting server is the error message:

This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.ArgumentException: This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection.”

This error message can be retrieved on the Event Viewer window on the server. If you do not have an access to the server, you may contact your hosting provider to trace this error for you.


This problem is caused by the fact that WCF only supports 1 IIS host header. Your hosting provider may have more than 2 host headers, namely and Therefore, you may need to remove one of the host headers from the IIS.

Other Alternative Solution:

The other alternative solution you can consider is to create a separate .SVC file. The solution, since WCF services hosted in IIS can have only one Base Address was to create a custom service factory to intercept and remove the additional unwanted base addresses that IIS was providing. Your default IIS settings will have 2 entries of host headers, namely: and You then need to customize your .svc file to specify a custom service factory. You are then able to create your custom factory by inheriting from ServiceHostFactory and overriding as required.The following is the code:

class CustomHostFactory : ServiceHostFactory
        protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
              CustomHost customServiceHost =
                new CustomHost(serviceType, baseAddresses[1]);
            return customServiceHost;

class CustomHost : ServiceHost

        public CustomHost(Type serviceType, params Uri[] baseAddresses)
            : base(serviceType, baseAddresses)
        { }
        protected override void ApplyConfiguration()

You need to pass through baseAddresses[1] (which was the www. address) but it would probably be wise to specify that address you want to prevent changes by your web host from impacting your code.Please refer to this article at for further information.

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