PyDSWS ConnectionError

I have trouble with the login

ds = PyDSWS.Datastream(username='XXX', password='YYY')

This raises a connection error:

ConnectionError: HTTPConnectionPool(host='product.datastream.com', port=80): Max retries exceeded with url: /DSWSClient/V1/DSService.svc/rest/Token?username=XXX&password=YYY (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x000000000A5FF588>: Failed to establish a new connection: [Errno 11004] getaddrinfo failed',))

How should I trouble shoot?