GetHttpConnection API throws "The operation timed out" exception.?

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C++

MFC

When i am using GetHttpsConnection API in a c++ program, i got an exception(CInternetException) "The operation timed out". I don't know the reason for it. Can anyone help me?
code section:

	CInternetSession	oInternetSession(_T("Watchdog"));
	UINT				nBytesRead ;
	CHttpConnection*    pConnection	= NULL;
	CHttpFile*          pHttpFile	= NULL;
	CString             strUserName = _T("");
	CString             strPassword = _T("");
	DWORD               dwStatusCode;
	char*               chBuffer    = new char[1024];
	CString             strLog;

	try 
	{
		pConnection = oInternetSession.GetHttpConnection(m_strHttpServer, 
		(INTERNET_PORT) m_nHttpPort, strUserName, strPassword);

		//Open Request and get the HttpFile
		pHttpFile   = pConnection->OpenRequest(1, m_strHttpObjectName ,NULL, 1, NULL,   NULL,INTERNET_FLAG_RELOAD); 
		//Send Request
		pHttpFile->SendRequest();
}
catch(CInternetException* pe)
{
	TCHAR ExcText[1024];
	pe->GetErrorMessage(ExcText, 1023);
	TRACE(_T("WinInet exception %s\n"), ExcText);
	strLog.Format(_T("Accessing Url: %s:%d/%s failed. Reason: %s"), m_strHttpServer,m_nHttpPort, m_strHttpObjectName, ExcText);
	m_pLogger->Log(LOGPRIO_HIGH, strLog);
	pe->Delete();
}

Thanks.