Ist still have this issue:
<TraceRecord xmlns="schemas.microsoft.com/.../TraceRecord" Severity="Error">
<TraceIdentifier>msdn.microsoft.com/.../System.ServiceModel.Diagnostics.ThrowingException.aspx</TraceIdentifier>
<Description>Throwing an exception.</Description><AppDomain>/LM/W3SVC/2/ROOT-1-131384374653104357</AppDomain><Exception><ExceptionType>System.ArgumentException, mscorlib, Version=4.0.0.0, Culture=neutral,
PublicKeyToken=b77a5c561934e089</ExceptionType><Message>The value could not be added to the collection, as the collection already contains an item of the same type:
'System.ServiceModel.Description.UseRequestHeadersForMetadataAddressBehavior'. This collection only supports one instance of each type.
Parameter name: item</Message><StackTrace> at System.Collections.Generic.KeyedByTypeCollection`1.InsertItem(Int32 index, TItem item)
at Microsoft.Crm.Extensibility.SdkServiceEndpointBuilder.AddDefaultPorts(ServiceHost serviceHost, PortSchemeDictionary portSchemes)
at Microsoft.Crm.Extensibility.SdkServiceEndpointBuilder.AddDefaultEndpoint(ServiceHost serviceHost, Type implementedContract)
at Microsoft.Crm.Extensibility.SdkServiceEndpointBuilder.BuildEndpoints(ServiceHost serviceHost, Type implementedContract, Func`1 messageInspectorFactory)
at Microsoft.Crm.Extensibility.SdkServiceHost.InitializeRuntime()
at System.ServiceModel.ServiceHostBase.OnOpen(TimeSpan timeout)
at System.ServiceModel.Channels.CommunicationObject.Open(TimeSpan timeout)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.ActivateService(ServiceActivationInfo serviceActivationInfo, EventTraceActivity eventTraceActivity)
at System.ServiceModel.ServiceHostingEnvironment.HostingManager.EnsureServiceAvailable(String normalizedVirtualPath, EventTraceActivity eventTraceActivity)
at System.ServiceModel.ServiceHostingEnvironment.EnsureServiceAvailableFast(String relativeVirtualPath, EventTraceActivity eventTraceActivity)
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.HandleRequest()
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.BeginRequest()
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.OnBeginRequest(Object state)
at System.ServiceModel.AspNetPartialTrustHelpers.PartialTrustInvoke(ContextCallback callback, Object state)
at System.ServiceModel.Activation.HostedHttpRequestAsyncResult.OnBeginRequestWithFlow(Object state)
at System.Runtime.IOThreadScheduler.ScheduledOverlapped.IOCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
at System.Runtime.Fx.IOCompletionThunk.UnhandledExceptionFrame(UInt32 error, UInt32 bytesRead, NativeOverlapped* nativeOverlapped)
at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)
</StackTrace><ExceptionString>System.ArgumentException: The value could not be added to the collection, as the collection already contains an item of the same type:
'System.ServiceModel.Description.UseRequestHeadersForMetadataAddressBehavior'. This collection only supports one instance of each type.
Parameter name: item</ExceptionString></Exception></TraceRecord>
can you tell me how to fix this ?