We're having trouble processing your request at the moment - Exchange 2010, SP3, RU1

Hi,

I've got the following co-existence scenario:

Exchange Server 2003, latest SP on Windows Server 2003

Exchange Server 2010, SP3, RU1 on Windows Server 2012

Mailflow, AutoDiscovery, free/busy replication all seem to work fine, however, when a user with a mailbox on Exchange 2010 logs on to OWA to check their group membership, set their OOO etc. an error as per title comes up. 

Anonymous authentication is enabled on the EWS and ECP folders, Windows authentication is enabled on the WebServices Virtual Directory.  HTTP redirect is enabled on the server (to https://mail.mydomain.co.uk). I've disabled that to test but hasn't made a difference...

Bindings for the default web site are * and 127.0.0.1 on HTTP and HTTPS.

Setting the OOO from Outlook 2010 works fine.

Errors are all similar to the message below (with various files).

I'm lost - does anyone have any ideas?

Thanks

Log Name:      Application

Source:        MSExchange Control Panel
Date:          27/07/2013 23:02:47
Event ID:      4
Task Category: General
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      xxx
Description:
Current user: 'mydomain.local/Domain/Users/OU/Test 2010'
Request for URL 'https://mail.mydomain.co.uk/ecp/MyGroups/MemberOfGroups.svc/GetList?msExchEcpCanary=nSHl5LxxCUig7boWjiDZVAEx6hxxWtAI4NIrCkuYli1tw8hiJ2VBOyymxHxS9vTAkGcWHlq-94Y.' failed with the following error:
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.TypeLoadException: Could not load type 'System.ServiceModel.Activation.HttpHandler' from assembly 'System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
   at System.Reflection.RuntimeAssembly.GetType(RuntimeAssembly assembly, String name, Boolean throwOnError, Boolean ignoreCase, ObjectHandleOnStack type)
   at System.Reflection.RuntimeAssembly.GetType(String name, Boolean throwOnError, Boolean ignoreCase)
   at System.Activator.CreateInstance(String assemblyString, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, Evidence securityInfo, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(String assemblyName, String typeName)
   at Microsoft.Exchange.Management.ControlPanel.WebServiceHandler..ctor()
   --- End of inner exception stack trace ---
   at System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandleInternal& ctor, Boolean& bNeedSecurityCheck)
   at System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
   at System.RuntimeType.CreateInstanceDefaultCtor(Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(Type type, Boolean nonPublic)
   at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
   at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture)
   at System.Web.HttpRuntime.CreateNonPublicInstance(Type type, Object[] args)
   at System.Web.Configuration.HandlerFactoryCache..ctor(String type)
   at System.Web.HttpApplication.GetFactory(String type)
   at System.Web.HttpApplication.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

System.TypeLoadException: Could not load type 'System.ServiceModel.Activation.HttpHandler' from assembly 'System.ServiceModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
   at System.Reflection.RuntimeAssembly.GetType(RuntimeAssembly assembly, String name, Boolean throwOnError, Boolean ignoreCase, ObjectHandleOnStack type)
   at System.Reflection.RuntimeAssembly.GetType(String name, Boolean throwOnError, Boolean ignoreCase)
   at System.Activator.CreateInstance(String assemblyString, String typeName, Boolean ignoreCase, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes, Evidence securityInfo, StackCrawlMark& stackMark)
   at System.Activator.CreateInstance(String assemblyName, String typeName)
   at Microsoft.Exchange.Management.ControlPanel.WebServiceHandler..ctor()