500 Server error when hosting WCF

Maybe you can help me because I am really at a loss here.

I am trying to host my WCF service on IIS on a subdomain.

To start, here is my file structure:

http://s18.postimage.org/eqmjxb00n/Serv.jpg

Inside the bin are my .dll representing my interface and it's implementation.

Here is the web.config file:

<?xml version="1.0"?>
<configuration>

  <system.web>
    <compilation debug="false" targetFramework="4.0" />
  </system.web>    
    <system.serviceModel>
        <services>
            <service name="AuthenticatorService.Authenticator">
                <endpoint address="" binding="basicHttpBinding" bindingConfiguration=""
                    name="AuthEndpoint" contract="AuthInterface.IAuthenticator" />
                <endpoint address="" binding="mexHttpBinding" name="MetadataEndpoint"
                    contract="IMetadataExchange" />
            </service>
        </services>
        <behaviors>
            <serviceBehaviors>
                <behavior>
                    <serviceMetadata httpGetEnabled="True"/>
                    <serviceDebug includeExceptionDetailInFaults="False" />
                </behavior>
            </serviceBehaviors>
        </behaviors>
    </system.serviceModel>
  <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>

</configuration>

It works locally but when I upload to IIS it just gives 500 server errors.

Thanks!

If it's any use here is the message from the detailed error page:

Module  ServiceModel-4.0
Notification    AuthenticateRequest
Handler svc-Integrated-4.0
Error Code  0x00000000
Requested URL   http://service.swiftposter.com:80/auth.svc
Logon Method    Anonymous
Logon User  Anonymous

Edit: I enabled ELMAH logging and finally got a meaningfull message:

System.ArgumentException: This collection already contains an address with scheme http. There can be at most one address per scheme in this collection. If your service is being hosted in IIS you can fix the problem by setting 'system.serviceModel/serviceHostingEnvironment/multipleSiteBindingsEnabled' to true or specifying 'system.serviceModel/serviceHostingEnvironment/baseAddressPrefixFilters'. Parameter name: item

Im going to start researching this error, but I posted here just in case someone knows what is wrong.

Stack Trace:

System.ServiceModel.ServiceActivationException: The service '/auth.svc' cannot be activated due to an exception during compilation.  The exception message is: This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection. If your service is being hosted in IIS you can fix the problem by setting 'system.serviceModel/serviceHostingEnvironment/multipleSiteBindingsEnabled' to true or specifying 'system.serviceModel/serviceHostingEnvironment/baseAddressPrefixFilters'.
Parameter name: item. ---> System.ArgumentException: This collection already contains an address with scheme http.  There can be at most one address per scheme in this collection. If your service is being hosted in IIS you can fix the problem by setting 'system.serviceModel/serviceHostingEnvironment/multipleSiteBindingsEnabled' to true or specifying 'system.serviceModel/serviceHostingEnvironment/baseAddressPrefixFilters'.
Parameter name: item
   at System.ServiceModel.UriSchemeKeyedCollection.InsertItem(Int32 index, Uri item)
   at System.Collections.Generic.SynchronizedCollection`1.Add(T item)
   at System.ServiceModel.UriSchemeKeyedCollection..ctor(Uri[] addresses)
   at System.ServiceModel.ServiceHost..ctor(Type serviceType, Uri[] baseAddresses)
   at System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(Type serviceType, Uri[] baseAddresses)
   at System.ServiceModel.Activation.ServiceHostFactory.CreateServiceHost(String constructorString, Uri[] baseAddresses)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.CreateService(String normalizedVirtualPath)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(String normalizedVirtualPath)
   at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath)
   --- End of inner exception stack trace ---
   at System.Runtime.AsyncResult.End[TAsyncResult](IAsyncResult result)
   at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.End(IAsyncResult result)
   at System.ServiceModel.Activation.ServiceHttpModule.EndProcessRequest(IAsyncResult ar)
   at System.Web.HttpApplication.AsyncEventExecutionStep.OnAsyncEventCompletion(IAsyncResult ar)

I fixed the error by adding this to my web.config.

<serviceHostingEnvironment multipleSiteBindingsEnabled="true" />

I think this happened because I had 2 bindings which both used http. Maybe someone else can elaborate.