Any request to CCMA Open Interface Service Request, return

<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
<s:Body>
<s:Fault>
<faultcode xmlns:a="http://schemas.microsoft.com/net/2005/12/windowscommunicationfoundation/dispatcher">a:InternalServiceFault</faultcode>
<faultstring xml:lang="en-US">Object reference not set to an instance of an object.</faultstring>
<detail>
<ExceptionDetail xmlns="http://schemas.datacontract.org/2004/07/System.ServiceModel" xmlns:i="http://www.w3.org/2001/XMLSchema-instance">
<HelpLink i:nil="true"/>
<InnerException i:nil="true"/>
<Message>Object reference not set to an instance of an object.</Message>
<StackTrace><![CDATA[at Nortel.Applications.CCMA.OpenInterfaces.SOAP..ctor()
at CreateNortel.Applications.CCMA.OpenInterfaces.SOAP()
at System.ServiceModel.Dispatcher.InstanceProvider.GetInstance(InstanceContext instanceContext, Message message)
at System.ServiceModel.Dispatcher.InstanceBehavior.GetInstance(InstanceContext instanceContext, Message request)
at System.ServiceModel.InstanceContext.GetServiceInstance(Message message)
at System.ServiceModel.Dispatcher.InstanceBehavior.EnsureServiceInstance(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage41(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage4(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage31(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage3(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage2(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage1(MessageRpc& rpc)
at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet)]]></StackTrace>
<Type>System.NullReferenceException</Type>
</ExceptionDetail>
</detail>
</s:Fault>
</s:Body>
</s:Envelope>

I've request with getServerList Method
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ser="http://www.nortel.com/soa/oi/ccma/service">
<soapenv:Header/>
<soapenv:Body>
<ser:getServerList/>
</soapenv:Body>
</soapenv:Envelope>

Any ideas?
Thanks in advance!