Dynamics Connector: [Customer Service to Account] has encountered an error. Processing will be aborted. Request Failed. See the Exception Log for details.

I am having trouble with a CRM and AX integration using the Microsoft Dynamics Connector.

All of my integration's are working except this one, and it was working at one stage and for an unknown reason just stopped working.

The stack trace error is:

--- Exception Dump ---

                Caught Exception: Request Failed. See the Exception Log for details.

                Stack trace:

Server stack trace:

   at System.ServiceModel.Channels.ServiceChannel.HandleReply(ProxyOperationRuntime operation, ProxyRpc& rpc)

   at System.ServiceModel.Channels.ServiceChannel.Call(String action, Boolean oneway, ProxyOperationRuntime operation, Object[] ins, Object[] outs, TimeSpan timeout)

   at System.ServiceModel.Channels.ServiceChannelProxy.InvokeService(IMethodCallMessage methodCall, ProxyOperationRuntime operation)

   at System.ServiceModel.Channels.ServiceChannelProxy.Invoke(IMessage message)

Exception rethrown at [0]:

   at System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg)

   at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)

   at ConnCustomerOrgService.getChangedKeys(ConnCustomerOrgServiceGetChangedKeysRequest request)

   at ConnCustomerOrgServiceClient.getChangedKeys(CallContext CallContext, DocumentPaging DocumentPaging, DateTime _changedDateTime)

   at System.Dynamic.UpdateDelegates.UpdateAndExecute4[T0,T1,T2,T3,TRet](CallSite site, T0 arg0, T1 arg1, T2 arg2, T3 arg3)

   at CallSite.Target(Closure , CallSite , Object , Object , Object , DateTime )

   at Microsoft.Dynamics.Integration.Adapters.AX2012.DynamicServiceObjectProviderBase.ReadObjectKeys(DateTime modifiedDate)

   at Microsoft.Dynamics.Integration.Service.MapThread.ProcessReads()

WARNING TID:67 [2013-06-07T15:47:53.2615122+10:00]: An unrecognized exception was thrown [mscorlib::0x80131501].

I have tried the following:

• Restart AOS instance
• Create a new mapping in the connector, and only map the AccountNum and AccountName fields
• Written a simple console app to call the method getChangedKeys, throws the same error message.

Has anyone else seen this? I've read that I can debug AIF services, so this would be my next step, however being a shared development environment I’m limited to doing this only when all other developers are offline which is often challenging.

Any other suggestions?