problem regarding ATL connection points...

I have created an ATL service which supports connection points. I have
created a method in my interface called DoTest() and also defined a callback
interface ItestEvents.

In the client side i am implementing the interface. Following is my client
code.

----------------------------------------------------------------------------------
DWORD dwAdvise;
CComPtr<Itest> pAdd;
hr =pAdd.CoCreateInstance(CLSID_test);

IConnectionPointContainer * pCPC;
IConnectionPoint * pCP;

hr = pAdd->QueryInterface(IID_IConnectionPointContainer,(void **)&pCPC);
hr = pCPC->FindConnectionPoint(IID_ItestEvents,&pCP);

pCPC->Release();
IUnknown *pSinkUnk;
CSink *pSink;
pSink = new CSink;
hr = pSink->QueryInterface (IID_IUnknown,(void **)&pSinkUnk);
hr = pCP->Advise(pSinkUnk,&dwAdvise);
hr = pAdd->DoTest();
pCP->Unadvise(dwAdvise); //call this when you need to disconnect from
server
pCP->Release();
CoUninitialize();
----------------------------------------------------------------------------------

Here the call to Advise() is returning -2147220990. Also my callback event
is not getting fired. I have implemented the callback interface as below

class CSink : public ItestEvents
{
private:
    DWORD m_dwRefCount;
public:
    CSink();
    virtual ~CSink();
  STDMETHODIMP OnTest(void)
  {
    AfxMessageBox("OnTest");
    return S_OK;
  }

HRESULT STDMETHODCALLTYPE QueryInterface(REFIID iid, void **ppvObject)
   {
        if (iid == IID_ItestEvents)
        {
            m_dwRefCount++;
            *ppvObject = (void *)this;
            return S_OK;
        }

        if (iid == IID_IUnknown)
        {
            m_dwRefCount++;
            *ppvObject = (void *)this;
            return S_OK;
        }

        return E_NOINTERFACE;
    }

ULONG STDMETHODCALLTYPE AddRef()
    {
        m_dwRefCount++;
        return m_dwRefCount;
    }
    
ULONG STDMETHODCALLTYPE Release()
    {
        ULONG l;
        
        l = m_dwRefCount--;

        if ( 0 == m_dwRefCount)
        {
            delete this;
        }
        
        return l;
    }

};

Please advice where have i went wrong...
Thanks in advance!!!!